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Dick Smith’s
Getting to hnow
PERSONAL COMPUTERS
Dick Smith’s
Getting to hnow
PERSONAL COMPUTERS
EDITOR:
DOROTHY DEGER
e
HORWITZ
GRAHAME
Castile Books ty
Published 1982 by agreement with
Universal Copyright Company (1959) ©
Distributed by Horwitz Grahame Books Pty Ltd,
506 Miller Street, Cammeray, 2062 and )
Gordon & Gotch Limited,
114 William Street, Melbourne, 3000, Australia
Copyright (c) 1982 by Horwitz Publications
National Library of Australia Card No.
and ISBN 0 7255 1332 2
All rights reserved
Printed in Australla by
Hedges & Bell,
Sutton Road, Maryborough, Vic. 3465
*Recommended price only
Photographs on pages 13, 29 (lower), 33: Courtesy, IBM.
4
Contents
INTRODUCTION 9
WHAT IS A PERSONAL COMPUTER
AND HOW DOES IT WORK? 11
The First Computerl/it'S Only A Machine/
Debunking The Myths/Anybody Can Oper-
ate A Personal Computer/Three Simple
Words You Need To Know/Hardware/Soft-
ware/Program/Hardware-Software Com-
patability/Are Computers Intelligent?/The
General Principles
THE COMPUTER MIRACLE 23
ae 2) A Primitive ‘Number Cruncher’/The
ae oa oe Analytical Engine/The ‘Amazing Tabula-
ting Machine’/Hilter’s Mistake/The Brits
Triumph/The Stored Program/The Sili-
con Chip/And The Future?
WHAT CAN A PERSONAL COMPUTER
DO FOR YOU? 35
Entertainment
Variety Of Games/Hand Eye Co-ordina-
tion/Good Old-Fashioned Fun.
Education
A Computer Has Indefinite Patience
Research
Household Management
Balancing The Budget/Your Bank
Balance/Preparing Your Income Tax
Return
Domestic Monitoring
Home Security
Hobby Cataloguing
“a Computing: The Hobby
Small Business Management
GETTING STARTED IN COMPUTING
AND CHOOSING THE HARDWARE 49
A ‘Hands-On’ Demonstration/Computer
ShowsiVisit A Computer Club/Start A Club
At School/Magazines And Books/Build Your
Own/Modular Computer Systems/Buy
From An Established Dealer
A CLOSE-UP LOOK AT TWO TYPICAL
PERSONAL COMPUTERS 55
System 80/TV Screen Or Monitor?/
Connecting Up/The Keyboard/Special
Function Keys/Built-ln Cassette Player/The
Central Processing Unit (CPU)/Your First
Program/Loading A Program/Writing Your
Own Programs/A Typing Error In Your
Program?/Recording Your Own Program/
VIC 20/What Is The Difference Between A
Game Machine And a True Computer?/A
Colour Machine/The Keyboard
THE RANGE OF READY MADE PROGRAMS 73
AKG Games/Educational/Business/General
Ae oS ex)
oy
Cas
EXPANDING THE SYSTEM 95
ER, Expansion Unit/A Second Cassette /Disk
- ¥; Drives/Printers/Light Pen/Music Syn-
— thesiser Unit/Speech Synthesiser Unit/
< ~~ ee Acoustic Coupler Modem/What Is MIDAS?
\ Sti, |
THE SMALL BUSINESS COMPUTER 110
The Options/20 Or Less Employees/Lack
Of Confidence?/Business Software/A Typi-
cal Business Computer
116
The Computer Number System/
Programming Languages/More About
Memory/The Operating System Pro-
gram/Disk Operating System (DOS)/
Bits, Bytes & Kilobytes/More About
Programming/Back Up/Systems/The
Basic Language/Variables/Operators
130
CLUB DIRECTORY 143
INTRODUCTION
Despite the growing stack of books, magazines and
newspaper supplements devoted to computers, even I’m
getting confused.
There is so much material (data, if you like) available
about computers but it is mostly too technical or confus-
ing for the average person to understand. And that, of
course, is the whole point about personal computers: they
are for the use and enjoyment of the average person with
very little technical knowledge, let alone a degree in
science or mathematics.
It seems to me that computers (and very often the
people who work with them) have been almost deliber-
ately shrouded in mystery and unnecessary mystique.
One of the aims of this book is to take computers out of
the closet and explain exactly what they are all about —
and what you can do with them — in simple, everyday
language.
Perhaps the fact that the development and introduc-
tion to the marketplace of low cost personal computers
has been so rapid (on sale in USA since 1975, Australia/
New Zealand since 1978, with literally millions sold) has
a great deal to do with the public’s confusion about
computers.
In other words, only yesterday a computer was solely
for the use of multi-million dollar big business and
government but today it is an affordable multi-purpose
machine available to the average person.
I also believe there is a basic misconception in most
people’s minds about personal computers. It’s easy (but
wrong!) to conjure up a vision of a space age housewife
pressing a few keys on her computer to magically clean
the house and prepare dinner for ten. Technically, that is
possible — but it would cost a fortune!
In my opinion a personal computer should be used
essentially as a source of enjoyment, education and as a
practical tool to organise various aspects of everyday life
or business. Really, there’s not very much difference
between the reason you'd buy a hi-fi system or a video
recorder and the reason you would buy a personal com-
puter. Incredibly, the price tag is much the same, but the
hi-fi and the video recorder are limited to one type of use
only while the computer is capable of numerous different
functions. |
This book explains all these functions and tells you
how you can get the most pleasure and practical use out
of your personal computer.
Strictly speaking, the word ‘personal’ 1s probably a
misnomer — as soon as you get the computer home you'll
find that the rest of the family will be clamouring to get
their hands on it!
From my experience young children adapt to compu-
ters particularly readily and are eager to learn the new
‘buzz words’ that are part of computer literacy. Yes,
there’s a whole new language out there — it’s fun to learn
and everybody will be speaking it soon. Let me give youa
few examples...
... ‘Hardware’ is not remotely related to hammers and
nails ... the ‘menu’ won’t be served at your favourite
restaurant... and a ‘brownout’ has nothing to do witha
day at the beach.
Crazy? Confusing? It won't be after you've read this
book and discovered the amazing and fascinating world
of computers.
Dik Smith
10
Chapter
O
What Is A Computer
And How Does
It Work?
WHAT IS A COMPUTER AND
HOW DOES IT WORK?
Simply defined, a personal computer is a small elec-
tronic machine, sold over the counter in retail stores, that
can be used for many activities in the home or small
business. Unlike other labour-saving machines which are
designed to do one job only, the computer is designed to
do many jobs.
It isan accountant one moment, a teacher the nextand,
if it’s time for games, a built-in amusement parlour in
your own family room. A very versatile appliance indeed!
It can even instruct you in the basics of flying (no, I’m not
kidding!), help sort out your income tax return and orga-
nise a business. (I’ll go into much greater detail in later
chapters but this should whet your appetite for now.)
A typical modern personal computer. It looks similar to a typewriter and is a
million times more streamlined than ...
12
... this 1954 IBM machine occupying a whole room!
The First Computer
It seems hard to believe but the first ‘modern’ computer
was built only about thirty years ago — a massive con-
traption, now a museum piece, that occupied an entire
room. Because of their size and cost (millions of dollars!)
early computers were limited to use by governments and
big business.
Today a personal home computer sits comfortably on
a desk or table and the price 1s within the reach of the man
in the street. (In my opinion, it is inevitable that the
personal computer will become as much an essential part
of the home as a refrigerator.)
The rapid development of computers to their present
stage has been nothing short of a miracle. It has been said
that if the car industry had accomplished what the com-
puter has in the last twenty years, a Rolls Royce would
cost $20 and do over 100 000 kilometres per litre.
The change in the state of computer art is very compar-
able to that of the calculator, now a familiar object in
13
most households. It was only a few years ago that calcula-
tors were bulky and expensive — today every schoolchild
considers the slim, inexpensive unit an essential tool for
maths and science classes. |
it’s Only A Machine
What has been responsible for the rapid development
of the computer? Probably the biggest uae factor ne
The very latest in silicon chips from IBM. All this complex and sophisticated
circuitry is contained in an area approximately 7mm square.
been the technology of the silicon chip (a tiny integrated
circuit) which has simplified and miniaturised computer
construction. It is not the intention here to explain that
dazzling technology in any detail — the purpose of this
book is to explain how to use the machine (remember,
that’s all a computer is!) not how to make it.
14
Debunking The Myths |
Up till fairly recently the very word ‘computer’ was
enough to make most of us recoil. ‘I don’t want to know
about it’... ‘It’s too complicated for me’... ‘I don’t have
the brains for this kind of thing’ would be. typical
responses.
Unfortunately, computers (perhaps because of their
complex beginnings) were put on a pedestal as objects far
too high and mighty for the average person to understand
And there is still something of a ‘holier than thow’ syn-
drome about them. One of the purposes of this book is to
debunk all the myths about computers — get them off
their pedestals and into the living room, or small business
office, where they belong.
One reason why people are frightened of computers is
because of the awesome reputation as mathematical genii
who can solve long equations in a single electronic beep.
Back in the early days computers were largely used
mathematically. For example, scientists operated them
as giant calculators to solve problems in aeronautical
design and the like. But a calculator can only deal with
numbers. A computer, on the other hand, can handle
much more than just numbers — it can deal with all types
of information in the form of words, music, patterns and
sounds, just to name a few.
The increasing use of computers in everyday situations
— making a theatre booking or buying an airline ticket —
is going a long way towards familiarising the public with
computers. And the time is not far off when we'll be doing
our grocery shopping by computer. (I’m proud to be the
first person in Australia selling electronic gear by compu-
ter shopping!)
Anybody Can Operate A Personal Computer
Admittedly, in the early stages of computers only
experts could operate them, but today’s personal compu-
ter is so sophisticated and, at the same time, so simple
that anybody can operate it. Certainly, there are quite a
few points to learn (that is another reason for this book)
15
but in less than one minute (yes, you read it correctly. —
one minute) the average person, including children of'a
reasonable age, can operate a computer using ready made
programs. It will take a little longer to learn to write your
own programs, but even that’s not as difficult as you
might imagine either.
You'll be amazed how quickly young children adapt to computers. Unlike
many adults they have no inbuilt resistance to the electronic age.
Three Simple Words You Need To Know
Before going any further it is important to explain
three simple ‘computer literacy’ words. It is impossible to
discuss computers without understanding these words.
Their meaning may be unfamiliar to you now but they are
rapidly becoming part of everyone’s vocabulary.
16
Hardware
Hardware is a general term to describe the physical
computer itself plus all the bits and pieces built into it or
attached to it. In other words, the hardware consists of
the parts of the computer set-up that you can pick upand
hold in your hands.
Some typical personal computer hardware - all very portable.
Software
Software is a collective term to describe the various.
types of programs that are fed into the computer.
Program
This word is doubtless familiar to you — you probably
didn’t baulk at it when it was used several times in the
preceding paragraphs — but what is its exact meaning in
terms of computing?
17
A program is simply a set of instructions for the com-
puter to obey.
To understand the concept of a program think of a
computer as being like a pianola. A pianola 1s capable of
playing a huge variety of tunes but can only perform
when you ‘load’ a pianola roll to tell the instrument what
“Ua tadgy r
at AR xy;
“ BESTE
®. “PApaza,” ONT
A computer program in the form of a cassette. It is identical in appearance and
size to a_conventional music cassette.
18
Computer programs in the form of floppy disks. These are not unlike small
45 rpm records in appearance.
to do. Similarly, a computer can only perform when you
‘load’ a program, the set of instructions telling the
machine what to do.
Programs can be bought ready made in the form of a
cassette (looks just like the one you put in your tape
recorder), a disk (not unlike a small 45rpm record) or as
19
instructions written out on paper ready for you to-follow
by pressing keys on a keyboard (very much like an ordi-
nary typewriter). Or, you can write your own programs.
Most enthusiasts use their computer in both of these
ways.
By using programs written by somebody else you can
start to use your computer instantly — it’s as simple as
buying a cassette to put in your tape recorder or a record
to play on your hi fi set. |
Most machines are built to perform just one function.
e.g. a vacuum cleaner Is built, 1.e. ‘programmed’, to suck
in dirt or blow out air. But because a computer is ‘pro-
grammable’ it turns into a multi-function machine.
Hardware/Software Compatability
It is important to understand nght from the beginning
that the hardware and software must be compatible with
each other. In other words, Type X hardware (the com-
puter) will not understand Type Y software (the pro-
gram) unless they speak the same ‘computer language’.
Therefore, before you buy your hardware you must
make certain that there is an extensive range of software
that can be used with it. Otherwise it would be rather like
buying a 22rpm record player put out by some eccentric
manufacturer and then finding it extremely difficult to
buy 22rpm records!
Are Computers intelligent?
Don’t be fooled — computers can’t think. There is no
such animal as an intelligent computer — in fact they
have been called ‘high-speed morons’! The machine is
only as good as the person who is operating it, or who
wrote its program. How often have you had a mistake in
your department store bill described as a ‘computer
error” The chances are it’s not a computer error at all —
it’s a computer programmer error. The programmer, of
course, is human — the man or woman who prepares
orders or instructions to the computer.
20
Obviously the computer system can malfunction, but it
is a rare occurrence since computers are considerably less
prone to making mistakes than humans. A well designed
computer has a program built into it to recognise many
common mistakes. The machine stops and refuses to
continue until the human operating it feeds in the correct
information.
The General Principles
Having established some elementary facts let’s look at
how a computer works. The following explanation is
deliberately simplified to give the reader an instant grasp
of computer principles. Each function of the computer
will be dealt with in much greater detail in Chapter Five.
You're probably familiar with the word ‘process’ as
associated with computers. Look at it this way: just asa
washing machine ‘processes’ laundry from dirty clothes
to clean, so a computer ‘processes’ information or data to
produce an answer or result. The operator gives informa-
tion to the computer (i.e. programs it) by inserting a
cassette or disk or pressing keys marked with letters,
numbers and symbols. This is known as /nput.
The computer then processes this data using informa-
tion either permanently or temporarily stored in its
memory and replies with an answer or question (there is
often a dialogue between operator and computer before a
result can be established) that is either displayed on a
monitor screen or printed out on paper. This is knownas
Output.
Diagrammatically, the operation looks like this:
STORED
COMPUTER MICRO- OUTPUT
INFORMATION PROCESSOR
(MEMORY)
21
Although the general principles of computing can be
shown in such a simple form, it has taken hundreds of
years and the genius of countless scientists to develop the
computer to its present stage. It’s an intriguing story...
22.
Chapter
The Computer
THE COMPUTER MIRACLE
Today’s computer has only been in existence for a mere
blink of history’s eye, but humans have been calculating
data since the beginning of time. Prehistoric man proba-
bly scratched marks on a rock to tally up the count of
animals killed for food, while another series of marks
would calculate the additional number of kills necessary
to feed the primitive community.
Not quite so ancient, but still dating back over thou-
sands of years, is the abacus. Old as it is, this quite
sophisticated means of calculation remains very much in
use today in the East.
N
NUMBER REPRESENTED
A Chinese abacus. (Crown copyright. Science Museum, London)
A Primitive ‘Number Cruncher
The honour of inventing the first Western mechanical
calculator must go to the Frenchman, Blaise Pascal, a
philosopher.and mathematical genius of the mid seven-
24
Museum, London)
PALE PELE
Fhe interior of Pascal's machine. (Crown copyright. Science Museum, London)
25
teenth century. Today his collection of cogs, wheels, nuts
and bolts would seem primitive in the extreme. Although
his machine was much praised and worked admirably
well as a ‘number cruncher’ there were not too many.
buyers. The machine was not cheap and even then there
was employee resistance not unlike the current situation
where some workers fear that the computer will do away
with their jobs. Pascal is well remembered in modern
computing since one of the major computer languages is
named after him.
Following Pascal a number of eminent European
mathematicians pursued the perfection of the mechanical
calculator. Perhaps the early nineteenth century English-
man, Charles Babbage, was the most successful. A
wealthy man in his own right, Babbage used his personal
fortune, as well as twisting the government’s arm to
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An artist’s impression of a model of the Difference Engine.
26
provide even more funds, to build a machine known as
the Difference Engine — a wonder of yet more wheels,
cogs, sprockets and levers.
The Analytical Engine
His work was viewed with great respect by the Royal
Astronomical Society, but Babbage was not satisfied. He
had his heart set on building a new and much improved
machine based on a very ingenious theory. From the
concept of this machine Babbage must be credited with
inventing the basic principles of a computer, i.e. a
machine that has no fixed function but can be ‘pro-
grammed’ to doa variety of different things. The machine
— that was destined never to be completed — even had a
‘memory’ where numbers could be stored awaiting their
turn to be summoned by the controller to perform the
A front view of portion of Babbage's Analytical Engine. (Crown copyright. Science
‘Museum, London)
27
next function. Babbage named his dream machine the
Analytical Engine.
Unfortunately, it was not long before Babbage’s dream
turned into the government’s nightmare. A disgruntled
Treasury closed its fist, and Babbage was left without a
financial backer. Benjamin Disraeli, the Prime Minister
of the day, was moved to remark that the only use he
could see for Babbage’s machine was to calculate the
enormous amount of money that the government had
poured into a worthless project. Babbage died a disap-
pointed man, judged by his contemporaries as a genius,
but misguided.
The ‘Amazing Tabulating Machine’
The next computer breakthrough came from across
the Atlantic in the United States. A predicament had
arisen there which once again proved the truth of that old
adage ‘Necessity is the Mother of Invention’. It was 1880
and the Eleventh Census had just been taken. But it was
readily apparent to those whose task it was to count and
record the results that this would take years and the
census would be completely out of date before the results
were published.
So, with typical Yankee ingenuity, the powers that be
decided to run a competition for an invention that would
enable the results of the next census to be collated in
record time. The winner of the contest was a Dr Herman
Hollerith who had invented ‘an amazing tabulating
machine’. Although the device was mechanical in princi-
ple, Hollerith had an advantage over his predecessors.in
being able to take advantage of that new-fangled Power
source — electricity.
The 1890 census was duly held and the statistics were
released in the unheard time of six weeks after census day.
Dr Hollerith went on to form the Tabulating Machine
Company which rapidly expanded in size and profit.
When he died at age 99 Hollerith was still acting as a
consultant to the company he had founded — but the
28
us
Lae NE
An engraving of Dr Hollerith’s sorting, counting machine of 1890. (Photo: Science
Museum, London)
One of IBMs first computing products — a 1901 hand-operated punch.
29
company name had been changed to International Busi-
ness Machine Corporation (IBM).
Hitler’s Mistake
During the first half of the twentieth century scientists
on both sides of the Atlantic were gradually developing
ideas to make computing machines faster and more effi-
cient. In the 1930s two Germans, Konrad Zuse and Hel-
mut Shreyer, were very much in the forefront of the
development of ‘high speed’ computers using valves
instead of electro-magnetic relays. In fact, shortly after
the outbreak of World War II, they suggested to the Nazi
authorities that they should build a computer which
would break the enemy codes and effect a quick German
victory. When asked by the authorities how long such a
machine would take the build, the two inventors ans-
wered, ‘Over a year’. The Nazi authorities laughed. This
did not fit in with Hitler’s timetable for World War II — it
would be well and truly finished by then. So the idea was
scrapped.
Ironically, the British, with their backs to the wall, had
to take a much more open ended approach to the war
timetable. The Bnitish military strength was no match for
Germany’s; the island population was totally outnum-
bered and out-weaponed. So, with nothing to lose, the
Brits decided that one way to win the war (or, at least, not
be defeated so quickly) was to crack the German codes.
The Brits Triumph
So began one of the strangest recruitment drives of the
entire war effort. The authorities gathered together_a
group of mathematical and electronic wizards and
secreted them in a Hertfordshire country mansion called
Bletchley Park. It was the stuff of which spy movies are
made, although the setting would have been more
appropriate for an Agatha Christie thriller.
The plan was totally eccentric — but, amazingly, it
worked. Using valves, the select few created the first
electronic computer and broke the German codes. Many
30
historians believe that this achievement won the war for
the Allies. It is important to remember though that this
computer series (known as Colossus) was only a special
purpose computer.
The first all-purpose general electronic computer was
an American achievement. Cumbersomely known as
Electronic Numerical Instigator and Calculator (affec-
tionately known as ENIAC), it was the world’s first ‘mod-
ern’ computer. First operated in 1944 — it was massive,
costly and with severe limitations.
The Stored Program
The most obvious limitation was the fact that to
change from one program to another, part of the compu-
ter had to be rewired! Enter the American mathematician
Jon van Neuman. More than any other individual this
man was responsible for the next vital step in the develop-
ment of the computer — the stored program. This is the
technique of feeding the complete program into the com-
puter’s memory and keeping it there permanently in its
entirety.
This explanation of a stored program is more easily
understood if a computer 1s again compared to a pianola.
A pianola can only ‘run’ its program (the roll) once
without it being physically reinserted into the pianola to
‘run’ again in strict consecutive order. The situation was
much the same with early computers and programs.
However, the development of the stored program pres-
ented two distinct advantages.
Firstly, the program could be repeatedly used without
having to be fed back into the computer each time.
Secondly, the computer had become a ‘decision maker’
since it could refer to any part of the program instantly
and at will without having to go back to the beginning of
the program and run it consecutively (like the pianola
roll) until a wanted piece of information was located.
The stored program was a great breakthrough in prac-
tical computing but the cost of building such a machine
still remained astronomical. The valves (at $10 a time)
31
were a crippling expense. Then, almost out of nowhere,
Bell Telephone announced the invention of the transistor.
Cost: 10 cents. And computers were on the move again
... the electronic revolution was gathering momentum.
But, marvel as it was, the transistor was to be only a
short-lived miracle. A replacement was just around the
corner. It was discovered as a by-product of the 1960s
Space Race to put a man on the moon. The staggering
amounts of US government money injected into research
during this period produced many scientific discoveries
— not the least of which was enormously complex elec-
tronic circuitry contained in a very tiny space. This was
the birth of the silicon ‘chip’ or integrated circuit — and
sO microelectronics had replaced the transistor.
The Silicon Chip
The silicon chip, smaller than your little finger nail and
costing only a few dollars, is today’s equivalent of a half
million dollar computer occupying a large room in 1959,
the year before Kennedy announced the man on the
moon program.
Not only did the development of the silicon chip con-
tribute to previously undreamed of technology, but it
also sent prices and sizes plummetting downwards.
The arithmetic goes like this. Valves (the basis of the
First Generation Computers) costing $10 were replaced
‘-by transistors (Second Generation Computers) costing
10 cents. Then came the silicon chip (Third Generation
Computers) costing a few dollars but the equivalent of
100 000 transistors.
According to one calculation: ‘If the dollar had inflated
at the same rate at which electronic costs have deflated, a
sandwich that cost you a dollar in 1950 would cost you
$20 000 today.’ (Running Wild, Adam Osborne.)
And The Future?
The electronic revolution is changing the face of the
earth. That is Fact One. Computers, the central core of
the revolution, will affect the lives of every person on this
32
Back in 1959 all these components were needed to make up a miraculous new
data processing computer from IBM.
=
ee
awrerwens
%
omputer (the real thing near completion and the
model proudly displayed in foreground) was marketed at nrices upward of
-$10 million.
33
planet, and beyond. That is Fact Two. Fact Three? Well,
there'll always be Death and Taxes, but I sincerely believe
that there are undreamed of benefits to be reaped by
everybody who has the privilege of living in a compute-
rised world controlled by humans.
Chapter
What Can A Personal
Computer Do For You?
PP x
35,
WHAT CAN A PERSONAL COMPUTER
DO FOR YOU?
Even if this book were to expand to encyclopaedic
proportions there is absolutely no way it could describe
everything a personal computer can do for you. The uses
are infinite — limited only by your imagination. (I know
a gynaecologist who has worked out a way to use a
personal computer to calculate the weight of an unborn
baby — don’t ask me how, but that’s where his imagina-
tion led him!)
Perhaps the best way to give you some practical ideas
about a computer’s potential capabilities is to separate
them into different categories. The categories are not
listed in order of importance — it is entirely up to you to
decide what area (or areas) of computer use appeal to you
as being the most interesting or valuable. The categories
are not totally separate either, of necessity they overlap.
@ Entertainment
e Education
® Research
@ Household Management (accounts, etc.)
® Domestic Monitoring
@ Hobby Organization
® Computing: The Hobby
© Small Business Management.
ENTERTAINMENT
The moment you carry a personal computer inside
your front door, you have created an instant home family
entertainment centre. There are literally hundreds and
hundreds of absorbing games you can play simply by
turning on the power and loading a cassette tape or a disk
programmed as a game. There you have it — the screen
lights up with Galaxy Invasion or a challenging game of
chess!
36
A small selection of the vast range of cassette programs available for personal
computers.
Huge Variety Of Games
There is an enormous variety and range of games
available, and your only problem will be to choose from
such a tempting selection. (See Chapter 6 for a rundown
on just a few of the games you can select from.)
Computer games are an economical form of amuse-
ment too. The average price of the software (the game
program) is about $20.00 (some are cheaper, some are
more expensive) — and that’s a once-only cost. Your
computer doesn’t eat 20 cent pieces and your children are
not wasting their pocket money in some sleazy amuse-
ment parlour. The only expense in playing computer
games aS many times as you like (beware — they’re
addictive!) is the electrical power used — which is min-
imal. (A switched on computer and video display screen
consume about the same amount of power as a modern
TV set.)
Hand/Eye Co-ordination
An interesting and beneficial side-effect of playing
computer games is the way in which they develop
37
hand/eye co-ordination skills, particularly in young
children.
Some of the games also have an educational aspect
included as part of the fun. For instance, in several of the
space invader type games the player will have to solve a
simple arithmetical problem before the computer will
allow the space craft to land and proceed with the next
part of the game. Children respond very well to this,
working out the arithmetic quickly and accurately with
an enthusiasm that is often lacking in a conventional
learning situation.
Many of the game programs are computerised versions
of popular games such as poker, chess or bridge. The
difference here is that you are pitting your skills and wits
against a computer. (Don’t worry, the computer is far
from infallible — I’ve called its bluff in poker many a
time. To add reality to the game, the person who wrote
the game program has allowed for the human factors of
bluff, gamble and greed.)
Good Old-Fashioned Fun
Although there can be some educational value in these
computer games, it is stressed that their main purpose is
for entertainment and enjoyment. There’s certainly
nothing wrong with good, old-fashioned fun for its own
sake.
One final point which the seventeenth century Pascal
would never have imagined in his wildest dreams —
computer games are a definite deterrent to parental
insanity on rainy days during the school holidays!
Remember, to play these games, you don’t have to
know anything at all about computers — it’s simply a
question of plugging in the power and loading the
Cassette.
38
We:
Is Dad worried that he won't score as high as Junior in the Meteor Mission
earne? Computer games develop a high level of hand/eye co-ordination at an
early age.
EDUCATION
Have you ever wanted to learn to type, but never had
the time to attend classes? There is a ready made program
— called Typing Tutor — which will teach you as effec-
tively and perhaps more quickly than attending formal
lessons in a classroom. After each lesson your perfor-
mance is evaluated, i.e. the computer displays your
degree of accuracy and number of words per minute
typed. If you are satisfied with your own performance
you can proceed with the next lesson or, if you prefer, you
39
can repeat the lesson as many times as you like. The
computer is your devoted slave-teacher.
Want To Be A Pilot?
Learning to type is just one of hundreds of ready made
teaching programs for all age groups. The children (or
you!) can learn to spell, practise maths, study a foreign
language, develop speed reading skills, learn the basis of
flight, study music ... the list goes on and on.
A Computer Has Infinite Patience
A computer has infinite patience when used as a teach-
ing aid. It never becomes cross or bored — and it never
has favourites.
If you don’t do well in a test the machine does not
become annoyed. It simply suggests that you might like
to try the test again, perhaps at a lower level of profi-
ciency, until you have mastered it. The computer always
offers its pupils a choice.
The computer is not impersonal either. It asks your
name and the lesson 1s directed at you personally, with
your name appearing on the screen. The results of all
lessons are graded by the computer, which always marks
fairly and accurately. There are very few children (or
adults for that matter) who won't feel a sense of pride
when a flashing box appears on the screen with the words
‘CONGRATULATIONS DICK, YOUR SCORE IS
100%’.
RESEARCH
You've probably heard of data banks that store infor-
mation on all sorts of subjects ranging from medical
research to the latest stock exchange prices. But did you
realise that your computer can give you instant easy
access to the thousands and thousands of documents
stored in data banks all over the world?
This might sound like a glimpse into the distant future
but it is actually happening now!
All this is made possible by a neat little unit called an
acoustic coupler modem, a communications network
40
called MIDAS and your ordinary telephone: Full details
are given in Chapter 7.
HOUSEHOLD MANAGEMENT
Unless you run a mansion the size of Buckingham
Palace with a commensurate number of staff, there is
absolutely no need to call in IBM to design a special
computer to manage your household. Your personal
computer will do just fine.
Balancing The Budget
Balancing the household budget is something that
comes more naturally to computers than it does to most
humans. Not everyone has the innate mathematical abil-
ity to control accounts, which is probably why some of us
mismanage the family budget — or don’t have one at all.
The computer can competently take charge of your
household accounts and general budgeting. There are
ready-made programs available for these purposes but if
you find you have an aptitude for programming you may
want to develop your own program, specifically tailored
to your particular household.
Your Bank Balance
There are very few people who have not had the expe-
rience of being at odds with the bank over the exact sum
of money in the account. (Infuriatingly, the bank’s com-
puter is nearly always right!) So, as the old saying goes, if
you can’t beat ’em, join ‘em.
To find out your bank balance with precision accuracy
all you have to do is feed into the computer the deposits
made, cheques written, plus any bank charges or periodi-
cal payments. Then, at the press of a button, the compu-
ter will display your current bank balance.
Sure, you can do all this by hand, but the computer is
quicker with a built-in mathematical ability.
Can the computer make a mistake in calculating your
bank balance? No, the computer cannot make a mistake,
but if you feed in an incorrect piece of information (for
41
example, you tell it you wrote a cheque for. $20 when the
amount was actually $200) it is quite obviously going to
give you the wrong balance. The mistake is yours, not the
computer’s. (‘Garbage in, garbage out’ is a proven com-
puter adage.) |
Preparing Your Income Tax Return
This is an excellent use for your personal computer. It
is very easy to make an error in calculation when prepar-
ing your tax return by hand. This holds up your return
and increases the time taken to process it. Not only does
the computer fill in a return more efficiently and method-
ically than you, it does the job considerably faster ...
which means you get your refund cheque sooner!
There is an excellent income tax program available
written especially for Australian conditions.
Other Aspects Of Household Management
Depending on how much time you have at your dispo-
sal there is practically no limit to the amount of house-
hold organisation you could program a computer to
control. Some people make an inventory of their pantry
cupboard and use the computer for grocery stock con-
trol. (Personally, I reckon this is probably more trouble
than it’s worth ... unless you have an exceptionally large
and hungry family!)
You could also use your computer to catalogue all your
favourite recipes. Then, at the press of a few keys, the
screen would display a selection of recipes all featuring
the mince meat you’ve decided to prepare for dinner.
(Again, I’m not so sure that this 1s of any real benefit, but
I daresay it would be of interest to some people.)
You could even use your computer to organise your
Christmas card mailing list ... inventory the household
records :.. or catalogue your cassette or butterfly collec-
tion :..
The possibilities are endless. Once again, it’s your
imagination, time and skill that count.
42
The recipe book of the future?
DOMESTIC MONITORING
The use of computers in controlling domestic applian-
ces is quite advanced. In fact, there is no real limitation to
the computer’s ability — the only limitations are in your
ability to program the computer to do what you want, the
engineer’s ability to produce the hardware to attach to it
and, very important, the cost involved.
The principle behind computer control of a household
appliance is very simple. Take your oven, for example, A
small electrical device called a relay can be attached to the
normal on/off. switch to start or stop the oven at a
predetermined time or temperature. This relay may be
activated by an infra red light that is controlled by the
program you have fed into your computer. There need be
no physical connection whatsoever between the compu-
ter and the oven.
This example is meant only to illustrate the principle of
computer control. In reality, it would be a complete waste
of time, effort and money to computerise your oven —
the manufacturers have already done it for you by supp-
43
lying an in-built automatic on/off timer and. control in
most modern ovens.
Using the same relay principle a computer can be
programmed to turn lights on and off at regular (or
irregular) times when you are away from home. Once
again, if you only want a few lights controlled, it’s hardly
worth the expense of a computer system when you can
buy a ready made light off/on system for far less than a
computer set up would cost.
However, if you wanted to go all the way and be able to
turn on/off lights, radios, TVs, video recorders, electric
blankets and even the air conditioning in the dog’s ken-
nel, you could purchase a control device (it has about 16
channels and uses normal radio frequency) which, when
linked with your programmed computer, will control all
these appliances and more. (Maybe that’s going a bit far
— but I guess it depends on what turns you on and how
much money you have to spare.)
Home Security
One domestic computer application which is of real
benefit is in the area of home security. If you install a
conventional noisy ringing burglar alarm, the problem is
that nobody takes very much notice of it. How often have
you heard an alarm ringing and done nothing about it?
Even neighbours are often loathe to interfere or call the
police. In any event, noise pollution laws only allow the
alarm to ring for a fairly short period of time.
It is now a proven crime statistic that a burglar is not
unduly worried by the sound of an alarm going off. He is
fairly confident that apathy will prevail and the law is not
likely to arrive in a hurry... so he continues looting. But
if your alarm is linked to-your programmed computer...
that’s a different story.
A soundless light sensor detects the burglar and alerts
the computer which automatically dials the police, issu-
ing a pre-recorded message that a burglary is taking place
at your address. The police can arrive swiftly and catch
the thief in the act without him being aware that any
a4
alarm has been sounded at all. This silent, computerised
alarm is an exceedingly valuable security aid.
HOBBY CATALOGUING
A personal computer is the ideal way to organise and
catalogue just about any type of hobby collection.
Stamps, coins, records, tapes, photographs, butterflies
... all manner of collections can be put in order with the
help of a computer.
A computerised record catalogue? Why not? You'll never lose track of your
favourite album.
45
Although there are some pre-written programs to get
you started, you would need to acquire some program-
ming skills yourself in order to take advantage of all the
computer has to offer.
COMPUTING: THE HOBBY
Learning to program a computer is an absolutely fasci-
nating hobby in its own right. It’s a very creative activity
to which you can rapidly become addicted . .. in the best
sense of the word! This book does not attempt to teach
you programming, but try the super simple program
written out on page 65. This is just a totally elementary bit
of fun — but it would spark your interest and stimulatea
desire to learn more.
As the computing hobby gains more and more devo-
tees, computer clubs are springing up all round the coun-
try. (See page 143 for Club Directory — maybe there’s
one close to where you live.)
Financially Rewarding Hobby
Programming can also be a very financially rewarding
hobby. Because most of the programs sold in Australia
have been written in the United States, often for situa-
tions and conditions which do not apply here, there is a
strong demand by software retailers for first class pro-
grams written for local conditions. (We’ve even pur-
chased programs devised by talented fourteen year olds.)
You really need a certain type of analytical mind to
become a good programmer. But you’ll never know if you
have what it takes until you get your ‘hands on’ a compu-
ter and a good instruction book.
SMALL BUSINESS MANAGEMENT
The use of a computer in a small business deserves a
separate chapter of its own. It will suffice to say here that
there are ready made software programs to take over
46
such aspects of a small business as:
© Accounts
© General Ledger
@ Inventory
© Stock Take
® Payroll
© Word Processing
Some fundamentals of business management can be
entrusted to the computer and hours of manual labour
One of the advantages of using a computer in a small business is that you can
tell at a glance just how the profit (or loss!) is shaping up.
CONCLUSION
The contents of this chapter are really only a general
guide to what a small computer can do for you. Just
reading the ideas and suggestions given here has probably
prompted your own thoughts on how you and the com-
puter could get together to benefit your particular lifes-
tyle or business.
47
Remember, the average personal computer costs about
the same as a good stereo system and has an infinitely
greater capacity for being enjoyed and used in thousands
of practical ways.
Chapter
Getting Started In
Computing And
Choosing The
GETTING STARTED IN COMPUTING AND
CHOOSING THE HARDWARE
You've already taken the first step in getting started in
computing — you are computer conscious. The fact that
you are reading this book proves it. You’ve become aware
of the increasing use of computers at work, at school or
simply in the course of everyday life.
(The other day my wife asked me to check that our
family health insurance was up to date, so I phoned the
company and was immediately asked for my-insurance
number. When I gave it I could hear the electronic sounds
made by the girl as she keyed my number into her compu-
ter. Within seconds she replied: ‘You’re Dick Smith from
North Ryde and your insurance is fully paid up till the
first of next month.’ A simple experience like this really
underlines the fact that we are in the computer age.)
A ‘Hands-On’ Demonstration
A good way to have your first close encounter with a
computer is to visit a shop where computers are sold and
there are demonstration models on view. M ost sales peo-
ple (particularly in specialised electronic shops) are
knowledgeable about computers and are only too pleased
to explain the product, demonstrate it, and let you get
your ‘hands on’ it.
Computer Shows
Spend some time at a computer show. These are being
held in the major cities with increasing regularity. All
types and brands of computers are on display and this
50
gives you an opportunity to compare the capability and
prices of the various brands. (I happen to believe that my
computers are the best — but others sell for more money.
My advice: compare all the different brands and see
exactly what you get for your dollars.)
Visit A Computer Club
Check around and see if there is a computer club in the
area where you live or work. You'll sometimes find these
clubs advertising in the local papers. Ask if you could
attend a meeting to see what goes on. Don’t be shy just
because you don’t know much about computing yet —
you'll find that most computer enthusiasts are very keen
to spread the word about the hobby and will enthusiasti-
cally give a newcomer many valuable tips.
Start A Club At School
If you’re still at school there’s bound to be a teacher
with a feeling for computers. Suggest to him/her that a
computer club should be started at school. Maybe the P
& C could be persuaded to donate some of their funds
towards the purchase of a computer.
Magazines And Books
Read all you can about computers. There are at least
two locally produced magazines devoted to personal
computing now appearing on newsagents’ shelves. Other
American and English magazines and books can be
bought at specialised shops.
Build Your Own
If you’re an electronic hobbyist but know very little
about computers, why not buy a kit and build your own
computer! It’s nowhere near as difficult as you might
think, and you'll save a considerable amount of money.
Most computers sold in Australia are manufactured in
the USA where extremely high labour rates prevail —
and you pay for this on built-up units. With a computer
kit, you provide the labour and therefore reduce the cost
very substantially.
Anyone who has a reasonably good knowledge of
electronics and can solder neatly should have no diffi-
culty in construction. This is because of a unique double-
sided circuit board design which means there 1s virtually
no other wiring. The board 1s covered with a professional
‘solder mask’ which makes soldering much easier and
eliminates the problems of bridges etc. Once the compo-
nents are soldered onto the board in their marked posi-
tion over 98% of the construction is completed.
An assembled computer kit.
52
Building a computer from a kit will teach you the
technical side of construction, how a computer works
and, soon, you'll learn to program. Conversely, if you
already know how to program but don’t know much
about the inside of a computer ... there couldn’t be a
better way to learn than by building a kit. All of which
gives you an excellent background for an exciting career
in computers, one of the growth employment areas of the
future.
Modular Computer Systems
Rather than have all the computer equipment inside a
single case, it is usually a wise decision to buy a modular
system. In this way you can add to the system as your
interest (and budget) increases. If you cannot add to the
system as you wish your initial purchase outlay is really
wasted money.
With some computers it can be a real headache to add
to the system later. What you want might not fit in the
unit — or if it does, you have to send your whole compu-
ter back to the factory for modifications. This is costly,
and you're without your computer.
If you want to add to your modular system all you have
to do is buy the new unit and plug it directly into the back
of your existing computer or expansion unit.
With many machines you’re locked into the expansion
facilities provided by the manufacturer — or lack of
them. Therefore, you would be wise to select a modular
computer that can accept expansion boards made by a
multitude of different manufacturers to cover almost every
conceivable type of computer application.
Service is another good reason for choosing a modular
system. Suppose a disk drive has a ‘bug’. With a onebox
system, it’s back to the factory again. Although the repair
might be simple, you’ll be days without your computer.
With the modular system, all you do is unplug the drive
and send it back for repair. In the meantime you've still
got the rest of your computer operating normally.
53.
Buy From An Established Dealer
Buying a computer is quite a sizeable investment so it is
extremely important to buy from a reputable shop that
has been in business for some time. The shop has its good
reputation to protect so you can be assured of good
aftersales back up service.
Although they are remarkably sturdy and tough, com-
puters do break down and you will want to be satisfied
that the firm that sold you the computer can carry out
warranty work and service the unit promptly. |
54
Chapter
5,
A Close-Up Look At
Two Typical Personal
Computers
A CLOSE-UP LOOK AT
TWO TYPICAL PERSONAL COMPUTERS
When you lift your new computer out of its box for the
first time you'll probably be surprised how light it is.
(Silicon chips don’t weigh much!) As youcan see from the’
photograph below it looks very similar to the familiar
typewriter.
SYSTEM 80
Now let’s run through the various components of one
typical personal computer, the System 80.
This unit, together with a display screen (either your
household TV screen or a video monitor) comprises a
basic personal computer set-up.
56
A green phosphor video monitor.
TV Screen Or Monitor?
Using a TV screen for the display saves a little cash on
your initial outlay but, in a family situation, can lead to
arguments when Mum’s favourite serial clashes with your
galactic battle. So you might want to buy a video monitor
as well, save fights... |
Video monitors have either white or green print on a
black background. The green-print type is slightly more
expensive but it is considered to be kinder to the eyes and
ideal for use over an extended period.
Connecting Up
The best. place to begin the close-up look is at the back
of the computer because this is where the various cords
that come in the box with it have to be connected.
37
© EXPANSION connector’ ©)
cas TAPE Sr ee ee
RECORDER MONITOR VIDEO CUT RESET
_ Power RF Output cable
Back of computer.
If you are going to use your TV as the monitor screen
take the RF output cable which is permanently connected
to the back of the computer and plug it into the aerial
socket of your TV, selecting Channel 1.
If you have a video monitor, plug the fat end of. the
single cord cable...
... Into the hole marked MONITOR on the back of the
computer; plug the thin end of this cable into the only
hole at the back of the monitor.
If you are going to use a program that has electronic
sound effects, take the second cable that comes with the
computer and insert the fat end in the hole marked TAPE
RECORDER in the back of the computer and the plug
on the thin white cord in the hole low down on the right
hand side in front of the monitor.
Pe Oa
ate one SSSI
Sy); a =
38
Before you plug in to the household power here is a
brief explanation of the other switches and buttons on the
back of the keyboard.
ON/OFF: Obviously, the on/off switch for the com-
puter itself.
VIDEO CUT: This button should normally be left out,
but press it in if you want to double the size of the letters
appearing on your monitor screen.
EXPANSION CONNECTOR: The outlet through
which attachments to the computer are. connected (see
Chapter 7).
RESET: Pressing this button ‘rubs the slate clean’. Any
program already stored in the computer’s memory is
immediately erased.
Now that the computer is connected to the display unit,
plug both units into the household power and let’s take a
look at the front of the computer.
IVueqwers ay 6 ; F IOS SIAL!
SSS EV OO chart cererstion stress hrgie tysters ae ae
£28 (Oj Bj C(O OjOiQjaeiVysie
RL SEE Te
The Keyboard
This is set out almost exactly like a typewriter with keys
for letters, numbers, symbols and a space bar. The posi-
tion of some symbols and computer command keys (such
as NEW LINE, also called RETURN or ENTER on
some computers) vary from computer to computer as is
the case with different brands of typewriters. One differ-
39
ence between a typewriter keyboard and a computer is
that the numeral zero is always printed with a slash
through it, @. This is because the computer’s ultra logical
‘mind’ could not otherwise tell the difference between a
zero and the letter O.
The keyboard is used like a typewriter to ‘input’ infor-
mation into the computer. The words you type (input)
on the keyboard display (output) on the video monitor.
Special Function Keys
PAGE: The PAGE button ts activated when the Video
Cut button at the back of the keyboard is pushed in.
When the button is up, the screen shows the left half of
the display; when the button is down, the right half of the
‘page’ is shown.
F1: When it is pressed down, this button turns on the
manual control keys for the built-in cassette player.
Built-In Cassette Player
The built-in cassette player, located on the right hand
side of the keyboard, 1s also an input device. It looks
exactly like a regular music cassette player and operates
in exactly the same way. The tapes you load in the
cassette player are re-written computer programs. (See
Chapter 6 for a guide to the type and variety of programs
available.) .
The Central Processing Unit (CPU)
This is located inside the keyboard unit and is the
‘heart’ of your computer containing its memory.
A computer has two different types of memory —
Read Only Memory (ROM): a fixed and permanent
memory which is built into the computer during manu-
facturing and used to store the operating system pro-
grams which process data input to the computer, run
your programs, and process output.
Random Access Memory (RAM): a reusable and tem-
porary (if desired) memory which is used to pag write
and store both programs and data.
60
The size of the computer’s memory (either type) is
expressed in terms of ‘kilobytes’ or, more commonly, just
the symbol K is used.
SSSR .
ra SRA AAA TAA_A_AKGEQgQ¥@B@Uw€«w€@€§*®™Qqw|ue_ Bian
=~
This photograph of the ‘guts’of System 80 pinpoints the location of both ROM
and RAM memory. The black perforated box on the upper right side is an
inbuilt power supply. Below this is the inbuilt cassette.
The System 80 has a 12K ROM (read only memory)
which gives you the full range of commands and func-
tions necessary for serious programming.
The same computer has 16K of RAM (random access
memory) which is more than ample for most people. Less
than 16K can be very limiting since the computer will
simply not have a sufficiently large memory to cope with
all the programs you want to use or write. If you become
really serious about computing, even 16K could be limit-
ing. However, it 1s generally a simple matter to expand
the computer’s memory (see Chapter 7). For additional
explanatory information about memory see Appendix.
61
Your First Program
Okay, let’s get started on your first program.
First switch on the video monitor (use the left hand
knob marked on/off — the other two knobs are for
contrast and brightness). If you are using a TV set you
may have to adjust the brightness/contrast controls or
the horizontal/ vertical holds to get a clear display on the
TV screen. Next, you're finally ready to turn on the
computer itself by pressing the switch at the back of the
machine. A small red indicator light above the keyboard
to the left will signal that the computer is on.
The word READY? will immediately appear in the top
left hand corner of the screen. Next press the key marked
NEW LINE and READY will drop vertically down to the
bottom left hand corner displaying like this
READY
> om
The > is the ‘prompt’ sign indicating that the computer
is ready to accept your instructions. The short line dash is
called a ‘cursor’. It indicates where the next character to
be typed will go.
Loading A Program
Now, assuming that you do not know (yet, at least)
how to program a computer yourself, it is simply a ques-
tion of loading a program that someone else has written.
Most personal computers come with a demonstration
cassette which you can run as your first program.
Step-by-Step
1. Take your cassette tape (I’ve chosen a game called
Poker Pete) and place it in the player in the normal way.
2. Press the button marked F1 on the keyboard to
activate the cassette player.
3. Press the rewind button.
4, When the tape is rewound, press the counter button
so that it reads 000. Also press the F1 button again, so
that it goes to its ‘up’ position.
Now you are ready to inform the computer that you
62
As you can see, a computer cassette program is placed i in the player in exactly
the same way as a conventional music cassette.
want it to load a cassette. There are several alternative
words used for this command — CLOAD (Cassette
Load) and SYSTEM being two of the most common. The
correct word to use is printed either on the package
containing the cassette tape or on the loading instruction
sheet that comes with it.
5. Type the word — say CLOAD — on the keyboard,
then press the NEW LINE key.
6. Press the Play button on the cassette. Within a few
seconds an asterisk will appear in the top right hand
corner of the screen. After a few more seconds the volume
meter above the cassette will activate — 1.e. move from
zero to the right.
7. Adjust the volume so that the needle is between 2
and 3. Some tapes require a slightly higher level of
volume — you just have to experiment to get the correct
level. A second asterisk, flashing intermittently, appears
almost instantaneously. This tells you that the program is
being ‘loaded’, or stored into the computer’s memory (the
RAM memory). The length of time taken for this proce-
63
dure depends on each individual tape — 6 to 8 minutes
would be average.
8. When the program is finished loading in,a READY
appears on the screen.
9. Now it’s time to type in the command word that
activates the taped program now stored in the computer’s
memory. The most common command word is RUN —
but check the instruction sheet that comes with the
cassette. Type in RUN, press NEW LINE...
Now it’s you v. the computer in a high stakes poker
game! Poker Pete will ask you your name, explain the
rules, shuffle the cards, deal the hands ... and the game’s
on. The computer keeps track of who’s winning the
money and, from time to time, presents a moving display
across the screen which reads THE LEADER IN THE
POKER TOURNAMENT IS ... POKER PETE!
(occasionally it says my name!) Poker Pete gives you the
option to fold if you have a bad hand and when you do he
responds sarcastically with NO GUTS HUH? ora series
of symbolised expletives.
VKH
64
(I haven’t chosen Poker Pete to illustrate a game
because I think it is one of the best. It’s just that it’s simple
— and fun at the same time. There are many more chal-
lenging games — both mentally and physically.)
There are hundreds and hundreds of programs availa-
ble in cassette form. See Chapter 6 for a list of just some
of the programs that are available. Remember, always
make certain when you buy software (i.e., a program)
that it is compatible with the hardware (i.e., your
computer).
Writing Your Own Programs
As has already been explained it is not the purpose of
this book to teach you how to program, but if you’ve
come this far the least I can do is show you a very simple
program. Actually, I’m going to make it so simple that
you probably wouldn’t recognise it as a computer pro-
gram ... but it is. And all types of computer programs
(including the complex scientific programs written to
guide Mariner to the edges of the planet Saturn) stem
from this process of basic logic.
Here we go:
1. To erase Poker Pete from the computer’s memory,
press the BREAK key, type in NEW and hit NEWLINE.
The word READY will appear in the top left hand
corner, followed by >-, and the computer is now ready
to receive your first program.
2. Type in
19 PRINT ‘DICK SMITH!’
3. Press NEW LINE
4. Type in
29 GOTO 19
5. Press NEW LINE
6. Type in
39 END
7. Press NEW LINE
This, what you see on the screen, is your program. It
consists of three instructions to the computer. Now type
65
the command RUN, press NEW LINE — and this is what
you'll see.
DUK BATH
HUCK SATTH
DICK SITH! I
The reason why the whole screen is flashing with DICK
SMITHs is because of your second instruction, 20 GOTO
19, and the fact that the computer takes everything you
say literally and logically. GOTO is a computer com-
mand word that means exactly what it says. The compu-
ter has been told to GOTO line 19, 1.e. carry out the line
19 instruction again, so it must continue to obey the
instruction and print DICK SMITH ad infinitum.
(Maybe ad nauseam is a more appropriate phrase!) The
computer cannot obey your instruction in line 39 to END
because the GOTO instruction in line 29 is self-
perpetuating. The computer does everything in strict
numerical order.
The number in front of each instruction is to identify
and separate each individual line of the program. The
reason for leaving a large numerical gap between line
numbers is to allow you the flexibility to add other
66
instructions which the computer will list and carry out in
numerical order. (See Chapter 8 for more detailed infor-
mation on programming.)
So much for my ego trip. Now, how about stopping the
program (use the ‘BREAK’ key), and typing in your name
instead of mine. The program will work exactly the same
way — the computer has no favourites!
A Typing Error In Your Program?
What happens if you make a typing error? Say, for
example, you've typed PLINT instead of PRINT. The
computer’s memory 1s programmed to understand the
word PRINT but the word PLINT is totally meaningless
to it. So, in response to your error, the screen will display.
2SN ERROR IN 10
(SN is short for SYNTAX)
Therefore you must type the whole line again correctly.
The computer will then automatically accept the new
correct line 19 and delete the incorrect line 19 from its
memory. |
If you see that you’ve made a typing error before you
have moved on to the next line, simply press the backs-
pace key (€—) to delete the incorrect letter(s) and retype
in the correct letter(s).
Recording Your Own Program
You can record your own programs on blank cassettes
(or on disk, see Chapter 7). A blank tape (it can be an
ordinary audio tape of reasonable quality) is placed in the
built in cassette unit and a program can be recorded using
exactly the same magnetic principle as in taping music or
speech.
A Display Of Garbage
Whenever you turn the computer off, wait at least 10
seconds before turning it back on otherwise your monitor
will display a load of ‘garbage’ — the whole screen 1s filled
with meaningless mumbo jumbo and strange symbols.
Don’t worry, you haven't broken the computer (that’s
amazingly difficult to do). Just turn it off and wait before
67
turning it on again, and the READY will display
normally.
In fact it is bad computer practice to turn the machine
on and off unnecessarily. Never do this when you want to
change from one program to another. Instead, press the
BREAK key (or the RESET button) and type in NEW to
erase the existing program from memory.
VIC 20
The second personal computer you’re going to take a
look at is less sophisticated and versatile than System 80
but sells for less than half the price. The VIC 20 is reallya
combination super game player/ baby computer. It has
enormous appeal to the many people who want more
than just an ordinary game machine as well as the facility
to practise computer operations which don't require
extensive memory and other very advanced features
found on more expensive computers.
SSS
SS
a
The Vic 20 ready to go!
What Is The Difference Between A Game Machine
And A True Computer?
A computer always has a fullsize typewriter keyboard,
not just a small calculator-type pad which can be difficult
to use. A computer can always use floppy disks (see
Chapter 7) as well as cassettes, whereas many game
machines can only operate cassettes. The machine lan-
guage is always built into a computer in the manufactur-
ing process so there is no need to pay extra for an
‘extended’ computing language as is the case with some
game machines.
The most obvious difference between the two types of
machines is that you can use your computer in all of the
fascinating ways described in Chapter 3, and not just asa
game machine.
A Colour Machine
This particular computer displays in colour either ona
video monitor or on the screen of a standard colour TV
set.
The same basic operating procedures that have already
been explained for System 80 also apply to VIC. This
computer does not have an in-built cassette player but it
1s Just a simple matter of plugging an external one directly
into the back of the computer which can be connected
either toa TV set ora video monitor. It also has sufficient
built-in expansion features to let the system ‘grow’ with
the user as his or her knowledge and requirements
become more demanding.
The Keyboard
Apart from the standard letters and numbers the VIC
keyboard is different from System 80.
A quick run through the uses of the various keys will
also give you a good idea of the machine’s capabilities.
Graphics And The Commodore Key
When you turn on the computer you are automatically
in ‘graphics’ mode which means you can type upper case
letters and the more than 60 graphics you see on the keys.
There are two graphics on each key. To get the graphic on
the right side, simply hold down the SHIFT key and type
the graphic you want. To get the graphics on the left side,
hold down the COMMODORE key (the little flag). In
this way, you can type upper case letters and the full
graphics set at the same time.
Upper/Lower Case And Graphics
To get into the ‘text’ mode you simply press the SHIFT
AND COMMODORE keys together. This lets you use
the computer like an ordinary typewriter, with full upper
and lower case letters, plus all the graphics on the left side
of the keys. These are the graphics that are most suited for
charts, graphs and business forms.
Colour
You can change the colours of the characters you type
by pressing the CTRL key and one of the 8 colour/
number keys. The colours are black, white, red, cyan,
purple, green blue and yellow. You can set — and change
— colours inside or outside a computer program. In
addition to the eight character colours you can also
change the colours of the border and screen on your
television or monitor set by typing a special command
called a ‘POKE’. You can get up to 255 different combi-
nations of screen and border colours, including 16 screen
colours and 8 border colours.
CTRL
As well as being used to set character colours this key is
70
also used to execute special commands in certain pro-
grams such as wordprocessing.
SHIFT
If there are two symbols, numbers or words ona single
key, pressing the SHIFT key at the same time as that key
will display or perform the function of the top symbol,
number or word.
The keyboard has two SHIFT keys and a SHIFT
LOCK key, just like a typewriter, for typing long strings
of upper case letters or graphics.
RUN/STOP
As its name implies, this is to start or stop a program
running. If you stop a program and want to resume it
where you left off, you can type CONT and the program
will ‘continue’.
RVS ON and RVS OFF
These two keys let you type reverse characters on the
screen. For instance, white on black instead of black on
white.
CLR/HOME
This key moves the cursor to the ‘home’ position at the
top lefthand corner of the screen. If you press SHIFT and
CLR/HOME you ‘clear’ the screen of all the characters
that were present.
INST/DEL
An editing key which lets you insert or delete
characters.
RESTORE
This is a ‘reset’ key. If you type the RUN/STOP key
and the RESTORE key together, you completely reset
the computer as if you just turned it on... with the benefit
that any programs you had in the memory are retained
and can be listed or run from the start.
CURSOR KEYS
These move the screen cursor up, down and sideways.
71
RETURN
This key serves the same purpose as NEW LINE in
System 80.
PROGRAMMABLE FUNCTION KEYS
The ‘function’ keys are in a vertical row on the far right
side of the keyboard. There are four keys and (if you shift
them) a total of eight functions. When a program is
running in the computer, it can ‘look’ to see if one of these
keys is being pressed — and do special things if one is
pressed.
This chapter has been designed as an outline guide to
the fundamentals of personal computers. The system can
be considerably expanded as you'll find out in Chapter 7.
No, it doesn’t get more complicated — it just becomes
more flexible and allows you more options.
72
Chapter
O
The Range Of Ready
Made Programs
THE RANGE OF READY MADE PROGRAMS
The programs listed and summarized in this chapter
are just the tip of the software iceberg. There are
hundreds and hundreds more available, with new ones
becoming available daily. The purpose of this general
listing is simply to give you an eye-opening indication of
the great variety of software in many different areas of
interest.
Remember, software and hardware must be compati-
ble — in other words, they have to be able to communi-
cate with each other in the same language. So, before you
buy a program, always check that it will suit your particu-
lar personal computer.
The software listed here is all suitable for use on Sys-
tem 80 computers. A similar range of software is availa-
ble for the VIC 20.
GAMES
Computer games have varying degrees of difficulty
ranging from fairly simple hand/eye co-ordination
movements to complex decision making/role playing
games which really tax your brainpower and your mani-
pulative skills.
Some individual games have various skill levels built
into the program. You are offered a choice of novice,
average or advanced levels, and asked whether you'd like
to play fast or slow.
BATTLE STATION
The aim of the game is to defend your space station
against the four attacking alien space ships. Cassette.
Needs 16K of RAM. $19.95. x-3596
74
GHOST HUNTER
You have to find your way through a ghost-filled maze,
eating dots as you go. If you’re too slow the ghosts will
get you — but if you’ve managed to eat a ‘power pill’
you'll get the ghosts! Cassette. Needs 16K of RAM.
$19.95. x-3597
KILLER BEETLES
Pit your skills against the killer beetles. You have to dig
traps and when a beetle falls in — you bury him. The
problem is: they don’t stay buried! Cassette. Needs 16K
of RAM. $19.95. x-3598
SPACE SHOOT OUT
A game for two players. Your aim ts to fire your
missiles through the meteorite belt to destroy the other
space ship. Cassette. Needs 16K of RAM. $19.95. x-3599
75
LUNAR LANDER |
You are the commander of a Lunar Lander whose auto
pilot has failed. It is your job to safely land the craft over
difficult terrains while maintaining a watchful eye on your
fuel load. Of course, once you have successfully landed,
the trick is to get out again. Cassette. Needs 16K of RAM.
$19.50. x-3691
GALAXY INVASION
You have to destroy the invaders and save the Earth —
but beware of roving flagships! Cassette. Requires 16K of
RAM. $19.50. x-3693.
COSMIC FIGHTER
Again, your aim is to destroy the alien invaders ... but
in this version of the game once you have destroyed the
aliens they all reappear ... and you have to kill them all
76
over again. This time around alien destruction requires
two hits. If you make it through, you then have to hit
them three times for an effective kill. A Mother Ship
provides refuelling and the menace of ever present flag-
ships adds to the excitement of this hard and fast game.
Cassette. Needs 16K of RAM. $19.50. x-309s
METEOR MISSION 11
Your mission is to rescue stranded astronauts from the
planet below. You must manoeuvre your craft through
the meteor belt to land, pick up and return the astronaut
safely to the orbiting Mother Ship. To make life harder,
the more astronauts you rescue, the more floating mete-
ors appear! Cassette. Needs 16K of RAM. $19.50. x-3697.
GALACTIC EMPIRE
A sophisticated game of strategy and tactics. Your
object is to unify the galaxy. Cassette. Needs 16K of
RAM. $19.95. x-3679
77
GALACTIC TRADER
The second of this now famous Galactic series. Your
objective is to make a fortune trading commodities
throughout the galaxy. Playing time is twenty minutes to
five hours, with ten levels of difficulty. Cassette. Needs
16K of RAM. $19.95. x-3678
GALACTIC REVOLUTION
The third of the Galactic series. Diplomacy, social
manipulation and Machiavellian ruthlessness must be
combined to bring the major power blocks of the galaxy
together to serve your ends as you lead the revolution (or
suppress it!). Cassette. Needs 16K of RAM. $19.95. x.3677
TAVALA’S LAST REDOUBT
The cruel Tavala has been forced from his throne in the
world of Galactica and has fled for his life to the planet of
Farside where he and his band of rogues plan their last
stand. Extreme solar conditions have isolated Farside
from the rest of the galaxy, so it 1s left to Berthi, the
Farside leader, to make the final assault on Tavala.
Cassette. Needs 16K of RAM. $19.95. x-3676
BETA BLITZ
Put yourself in the pilot’s seat as youapproach a city on
a high-speed bomb run. Your mission is to destroy the
enemy’s ground installations. Naturally, the enemy will
respond with rapid fire anti-aircraft guns and fighter
planes — they can mount a formidable attack! Cassette.
Needs 16K of RAM. $14.95. x-36s3
STAR WARRIOR
One of the popular ‘Adventure’ games; the scenery is
set as woodland and mountain terrain. Utilising good
78
graphics and various levels of play, your aim is to hunt
down the military governor of ‘Fornax’, and to destroy
the installation in which he is found. Nineteen command
options are available. Cassette. Needs 16K of RAM.
$39.95. x-3643
TREK 78
The classic computer game based on the popular TV
series Star Trek. This game provides continuous ‘status’
reports. Your aim is to destroy the enemy and save the
galaxy. Cassette. Needs 16K of RAM. $12.95. x-36u
POKER PETE
Like to play a game of poker with Pete? He’s a pretty
shrewd player — hard to beat, though it can be done. This
program has some quite intriguing graphics. Needs 16K
of RAM. $15.95. x-366«. |
3D TIC TAC TOE |
The familiar ‘noughts and crosses’ game, expanded and
made much more challenging. There are four grids on the
79
screen, one behind the other. You play the computer —
but watch out — it’s shrewd! Cassette. Needs 16K of
RAM. $17.95. x-367
SUPER MAZE
The maze game to end all maze games. It can generate
mazes of up to 100 x 100 elements — and it can take you
many hours to find the way out! Cassette. Needs 16K of
RAM. $17.95. x-37
FLIGHT SIMULATOR
A surprisingly good simulation of flying a small plane
— has excellent real time graphics. Learn basic flight
control, including take-offs and landings, then play the
exciting British Ace 3D battle game. Cassette. Needs 16K
of RAM. $34.90. x-3684
SIMUTEK PACKAGE ONE
Five space fantasy games in one package. Graphic-
Trek 2000, in which you try to dock the Enterprise with
its giant space station while avoiding Klingon torpedoes
and phasors (really good graphics). Invasion Worg,
where your job is to stop the Worg invasion of Earth
(multi-level game). Star Wars — where you must
manoeuvre your space fighter deep into the nucleus of the
Death Star, plant your bomb then escape via the only
exit. Space Target — a real-time space battle game with
impressive graphics. Saucers — a fast action graphics
game which calls for split-second responses! Cassette.
Needs 16K of RAM. $17.95. x-368s
DEATH TRAP
How’s your co-ordination between eyes and hands? In
this fast moving real-time graphics game you have to
control the motion of a constantly moving point on the
video screen, and avoid randomly-appearing ‘mines’ until
an ‘escape window’ appears. You can’t cross your own
trail, or hit the sides of the screen either. If you escape,
80
you get further tries — only it gets tougher! Cassette.
Needs 16K of RAM. $9.95. x-3688
SPACE INVADERS
The ever-popular arcade game that has become a cult.
Can you shoot down the aliens before they destroy you
and the Earth? Cassette. Needs 16K of RAM. $9.95. x-3699
TEMPLE OF APSHAI
This is the first of the remarkable ‘Dunjonquest’ series
and is one of the new breed of role playing games. “Tem-
ple’ offers you the chance to undertake heroic acts in a
labyrinth filled with treasures, traps and monsters. You
begin your adventures by bargaining with a tight-fisted
innkeeper for the weapons and armoury you'll need in the
Dujon. Cassette. Needs 16K of RAM. $39.95. x-36«1
HELLFIRE WARRIOR
Another of the ‘Dunjonquest’ series set in mediaeval
times. You commence by arming yourself with various
8]
weapons which may be purchased (bartered for) and you
are endowed with varying degrees of intelligence, ego,
intuition, strength and constitution.
Various levels of play are available with the goal being
to rescue the warrior maid Brynhild and return to ‘the
world above’ with her. Beware! Forty three monsters
await your every step — but some may be able to help
you. Traps, secret doors and treasures await the player.
Cassette. Needs 16K of RAM. $39.95. x-360
RESCUE AT RIGEL
You’re Sudden Smith, the intrepid space adventurer,
and your beautiful friend Delilah Rookh has been cap-
tured by the evil High Tollah inside a secret base on the
moonlet Rigel! You have to pick your way through the
various levels of the base, overcome the Tollah and his
cronies and escape with Delilah. The most impressive
program in the ‘Dujonquest’ series. Cassette. Needs 16K
of RAM. $22.50. x-36«9
82
CRUSH, CRUMBLE AND CHOMP
This movie monster game gives you a chance to
recreate just about any monster movie ever made. Only
this time you write the script. You direct the action. And
you get to be the star —the rea/ star — the monster!
Choose from six different monsters and let loose the
beast within you ... breathe fire, terrorize whole cities
(you have a choice of New York, San Francisco,
Washington DC and Tokyo) and snack on a horrified
populace.
But wait! The National Guard is out to get you. Even as
you read this a secret weapon is being readied against you
by mad and skillful scientists. Are you truly prepared to
face helicopters, tanks, artillery, and more, driven by
those who are literally dying to get you? Cassette. Needs
16K of RAM. $29.95. x-3650
(This is one of my favourite games — it really tests your
mental and physical skills.)
83
AIR TRAFFIC CONTROLLER
If you have ever wondered why air traffic controllers
are so highly paid, this game will show you. Your task is
to safely manoeuvre 26 aircraft between two airports
and/or various points within your control ‘area’. A time
limit of 99 minutes is allowed for completion of the task.
If you can plan ahead, it could lead to a new career!
Cassette. Needs. 16K of RAM. $12.50. x-3s:
ASYLUM
This is the latest ‘role-playing’ game, in which you have
to escape froma padded cellin the asylum. Many items to
help you can be found along the way, and the use of
ordinary English commands will determine your ability
to survive — but you'll need plenty of patience! Cassette.
Needs 16K of RAM. $19.50. x-3687
84
EDUCATIONAL
The computer is quickly becoming recognised as a
valuable educational tool for both adults and children.
of
MUSICAL COMPUTER
Written by an experienced music teacher, this program
helps the beginner learn to read music and find notes on
the piano keyboard — quickly and easily. Cassette.
Needs 16K of RAM. $34.95. x-3640
SPEED READING COURSE
A set of programs on two cassettes to help readers of all
ages improve their reading skills. Written by a NSW
primary school teacher, the programs have been deve-
loped from the West Australian Reading Development
Scheme. The four programs correspond to the first four
levels of the WARDS course, but can be set for reading
speeds as high as 0.1 seconds per line. Needs 16K of
RAM. $19.95. x-3602 |
TYPING TUTOR
A program that teaches you to touch-type. Claimed to
teach typing skills faster and more efficiently than any
other method, and has been widely acclaimed by business
colleges. The program monitors your typing skill contin-
uously, by checking the speed of response, and adjusts
your progress to suit. Cassette. Needs 16K of RAM.
$19.95. x-3682.
85
LEARNING FUN 1 — SCURVE INVADERS
A unique program that combines basic maths drill with
the ever-popular “Space Invaders’ game — practising
maths has never been so much fun! Before being able to
take each shot with the laser gun at one of the dreaded
Scurves, the player has to feed in the ‘correct data’ to the
spaceship’s computer. Tremendous fun, yet at the same
time very effective in developing proficiency in maths.
Sound effects, three levels of difficulty. Cassette. Needs
16K of RAM. $9.95. x-3694
LEARNING FUN 2 —
HANGMAN/CONCENTRATION
Two programs which are not only great fun to play but
also help to increase familiarity with words. Hangman is
the computer version of the well-known word guessing
game — complete with an animated graphics ‘man’ get-
ting hanged. The words can be chosen by either the
program, or a second player.
Concentration is the computer version of the well
known TV quiz game. Two players or teams have to
match prizes behind numbers on the screens, then guess
the mystery food word. Cassette. Needs 16K of RAM.
$9.95. x-3696
LEARNING FUN 3 — ALPHABET
COUNTDOWN/RHYME TIME
Alphabet Countdown is a real time graphics game in
which sets of words taken at random from a large group
must be placed in alphabetic order, in the shortest possi-
ble time. It has three levels of difficulty.
Rhyme Time displays a'series of unfinished rhymes,
and the player has to type in the missing word from the
clues given in the rhyme itself. There is no timing factor,
but after each rhyme the player’s current percentage cor-
rect is displayed. Cassette. Needs 16K of RAM. $9.95.
X-3698
86
BUSINESS
These programs have either been adapted to or written
specifically for Australian business conditions.
GENERAL LEDGER SYSTEM
e @PEX ELECTRONICS CO. DATE:- 26/27 @1 e
POSTING SUPARY POE 1
e BATCH 1ACCOUNT: ENTRY OR DETAIL 'DR: : @
ITEM 8 NUMBER! IDENTIFICATION CRs VALUE 1
SSNS OS OF 8088 SSS SES EE 6 OSE OSS SES SSSSSSE BOSS SSUS Sess eee esseeEsss
@ ’ 2? ES ICR: 2,000.00: @
8 33 'CREDIT SALES tCR: 1,000.00:
8 t tT 2DR: 1,000.00:
@ ’ 94 ICREDIT SALE COST tOR 94,06: @
i 75S INTEREST RECEIVED :CR: 125.00:
t ’ tOR 69.001
@ 8 361: CACCOMODAT TON IDR: 145.068 @
1 1660 sR 1DRt 16911.008
@ : DEBTORS TY 1,000.00: e
t 1708 tSTOCK ON HAND tDRi -1,094.06:
@ DEBIT TOTAL 3,125.00 e@
CREDIT TOTAL 3125.00 ;
Designed to overcome time consuming manual entry,
calculation and reporting methods. The package will let
you know exactly how your business is running, and
provide the necessary information to make ‘business
decisions’, based on accurate reports, as to your com-
pany’s status. |
Comes with a comprehensive manual. Disk. Needs
32K of RAM, two disk drives and an eighty column
printer. $299.00. x-3752
STOCK CONTROL & PRICING SYSTEM
Handles up to 1200 stock lines and offers many fea-
tures like Australian Sales Tax option, fast machine lan-
guage sorting, the ability to produce up-to-date price lists
at any time, a facility to print out stock count sheets and
compare counts with ‘on-hand’ figures. Disk. Needs 32K
of RAM and 2 disk drives. $275.00. x-3750
ACCOUNTS RECEIVABLE
This package gives you the vital information concern-
ing the ‘heart’ of your business, i.e. cash flow. At a glance
87
you can tell who owes you what, how much and for how
long, thus allowing you to. make important decisions
affecting your business.
Information that can take days to produce 1s available
to you in minutes. Your company’s financial status is at
your fingertips, with reports such as the Trial Balance,
Debtors Ledger and Posting summaries. Disk. Needs
32K of RAM, two disk drives and an eighty column
printer. $299.00. x756
WORP-1 WORD PROCESSOR
A low cost, easy to use basic word processor. Handles
1300 words/9000 characters at a time, features automatic
text wrap-around, character-orientated insert and delete
edition, optional justified printing. Needs 16K of
memory. Cassette. $59.50. x-37s8
WORP-9 PROFESSIONAL WORD PROCESSOR
A powerful professional word processor system which
is very easy to use. Written in Australia it provides unlim-
ited text insertion, the ability to print mailing labels and
to merge a name and address file with a standard form
letter. Disk. Needs 32K of RAM and at least one disk
drive. $299.00. x-3761
INVOICING
An invoicing program for the small business, making it
much easier and faster to produce invoices from mail or
telephone orders. Calculates tax if required, also handles
credit notes. Can be used either by itself, or with the
Stock Control and Pricing System (which lets it automat-
ically update stock levels as goods are sold). Disk. Needs
32K of RAM, 2 disk drives and a printer. $199.00 x-3751
DATA FILE MANAGER (DATFILE)
A program which lets you computerise virtually any
data file currently oncards, etc. Membership and mailing
88
lists, client and customer details, product information —
you name it. Datfile lets you call them up on the screen,
add new entries, make changes, sort all entries, select by
category, print out and so on. Disk. Needs 32K of RAM
and at least one drive. $99.00. x-370
GENERAL
LIGHT PEN DEMO CASSETTE
Provides two demonstration programs to get you
started with a low cost Light Pen. One side hasa Noughts
and Crosses game (also known as Tic-Tac-T oe), the other
has a simple ‘Menu’ program to show how you can use
the Light Pen with your own programs. Suits both 4K
and 16K machines. $11.95. x-3647
SKETCH-80
Use your Light Pen to ‘draw’ on the screen of your
computer. This machine language program lets you make
a drawing, modify it, store it away in memory, recall it —
even save it on cassette or disk. Fascinating and educa-
tional. Cassette. Requires 16K of RAM. $17.95. x-36a
89
SOUND-OFF
This package provides all you need to enter the exciting
world of computer sound effects and music synthesis.
There is a demonstration sound effect program plus a
program to let you add sounds to your own programs.
Cassette. Needs 16K of RAM. $14.50. x-3648
SHAREMARKET ANALYSIS
A very useful program for anyone who invests in the
sharemarket. It lets you store the selling price variations
for up to 45 shares (or indices), and produce either a
‘normal’ or ‘three point reversal’ point and figure chart
for any share or index whenever you wish. Much faster
than manual charting, and more flexible because you can
chart using any desired sensitivity! Disk. Needs 32K of
RAM, | disk drive. $49.50. x-3765
COMMUNICATIONS TERMINAL PROGRAM
This program lets you turn the computer into a com-
munications terminal, so that you can use it to obtain all
sorts of valuable information from the big ‘data base’
computers via your telephone. To use it your computer
must have an ‘RS-232C Communication Port’ card, and
an Acoustic Coupler Modem to connect to the tele-
phone. Cassette. Needs 16K of RAM. $9.95. x.3766
AUSTAX 82 |
A unique Australian-designed program written in
association with the Australian Taxation Department
and with the assistance of qualified tax specialists. It will
guide you through the complete tax form (Form S),
making sure that you don’t miss anything, and checking
your figures so that they don’t exceed allowable amounts
etc. Then it performs a complete calculation of your tax,
and gives you a summary so that you can transfer it to
your return. If you have a printer, it will print out the
summary so that you can attach it to your return as well.
Cassette. Needs 16K of RAM. $29.95. x-3762
90
ELECTRONIC SHOPPING
An exciting new program which lets you use your
computer to access the Electronic Shopping computer at
Dick Smith’s head office, in Sydney, using your tele-
phone from anywhere in Australia (or even overseas).
Lets you call up our computer, and either send in an
order, or call up any of the many ‘pages’ of useful infor-
mation which are available. Be one of the first to enter the
exciting era of electronic shopping! Disk. Needs 32K of
RAM. $5.00. x-3764
EDITOR/ASSEMBLER PLUS
A complete package for developing assembly/ machine
language programs. Has a text editor for preparing
source code, a powerful macro assembler for translating
the source into machine or ‘object’ code, and a very
flexible debug program to allow troubleshooting and
analysis of programs in memory. The debug program can
be used alone if desired. Cassette. Needs 16K of RAM.
$39.95. x-3680
Z-80 DISASSEMBLER
A program which produces an assembly language list-
ing from Z80 machine code stored in memory. Very
handy when you are trying to analyse machine language
or programs, to find out how they work (or why they
don’t!). This one is actually written in BASIC, and pro-
vides an ASCII decoding function as well as the mne-
monics — so you can spot stored messages, etc. Cassette.
Needs 16K of RAM. $17.95. x-3690
OS/80 (MICRODOS)
A low-cost disk operating system for systems which are
running from | to 4 disk drives (either 35 or 40 track). A
really easy to use DOS, designed especially for business
and professional use. It communicates with the user and
with user programs entirely by BASIC commands.
91
It has five utility programs on the disk (disk file
number, utility for formatting/ backup, etc. disk diagnos-
tic program, ‘patch’ program for updating the DOS itself,
and a simple data file program). Needs at least 16K of
RAM and one disk drive. $35.00. x-35ss
NEWDOS/8@ VERSION 2.0 |
A very powerful disk operating system for the more
advanced programmer. It provides virtually every func-
tion and facility which could be needed by even profes-
sional software development engineers. Comes complete
with a very comprehensive user manual, which is updated
by the publisher if you register as a user. Disk. Needs at
least 32K of RAM and one disk drive. $199.00. x-s56s
TINY PASCAL
Write and run your own programs in Tiny PASCAL
which has most of the basic statements and procedures of
full PASCAL. — _ supports recursive procedure/
functions, global and local variables, if-then-else-then,
peak and poke, while, for, repeat/ until and graphics.
Cassette. Needs 16K of RAM. $49.50. x-3670
PASCAL COMPILER VERSION 3.0
This program provides the computer with a full-scale
version of the popular PASCAL programming language,
featuring syntax error checking, access to the computer’s
normal graphics and random number generator. And
because it compiles your PASCAL programs directly
into computer language, they run very much faster than
BASIC programs. Disk. Needs 32K of RAM, at least one
disk drive, and NEWDOS/80. $239.00. x-366
OS-80 MACHINE LANGUAGE UTILITY
A utility which is used to adapt OS/80 (MICRODOS)
so that it can save and load machine-language programs
on disk. $39.50. x-ss60
92
Z-BASIC COMPILER
Lets you compile your BASIC programs, so that they
run up to twenty times faster than with the ROM inter-
preter. Disk version, but comes oncassette so you can use
it with the DOS of your choice. Needs 16K, but can
handle larger programs if you have 32 or 48K: $99.00.
X-3570
SOME COMMON BASIC PROGRAMS
Saves keying in the programs by hand. All sorts of
handy programs in BASIC: investment, statistics, tax
calculations, costing etc. Use the programs as they stand,
or adapt them to do what you want. $19.50. x-366
MMS FORTH V-20
A really well written implementation of the new
FORTH programming language. You can customise and
expand FORTH into virtually any language you need —
yet it runs from 10 to 20 times faster than ROM BASIC.
Disk, with its own DOS (written in FORTH). Minimum
16K of RAM and one disk drive. $85.00. x-366s
MEMORY AND DISK DIAGNOSTIC
A very handy program which lets you run basic trou-
bleshooting tests on your System-80 computer’s internal
memory, and its disk drives and controller. Lets you
check them out yourself if you suspect a hardware fault.
It can save you a lot of time and money, stopping you
from sending the equipment back for service when it isn’t
really to blame! Easy to use, it runs a comprehensive set
of tests on both of these important parts of the machine.
Disk. Needs at least 16K of RAM. $15.95. x.373
BASIC PROGRAM SERIAL LOADER
A program written especially to help schools, colleges
and others to transfer BASIC programs directly from
other computers (like the Apple II) into the System-80
93
computer, via the RS-232C serial interface. It therefore
saves all the effort of re-keying the programs into the
System-80, although the user still has to make any
changes to syntax that may be required before the pro-
gram will runcorrectly. Cassette, comes in three versions:
for 16K, 32K or 48K of RAM. Requires the RS-232C
serial interface option. $19.50. x-3689
For Adults Only
INTERLUDE
LS 7 cae ee vo 4
\\ \ N
‘ail
W
ee a wm -@w =.
ee ad - — ed
<<
A game for \ only. How’s your love life — getting
a little dull? When the kids have gone to bed, run this
program on your broad-minded computer and it will
come up with some imaginative ideas for the rest of the
evening ... Warning: not a program for those who are
offended by explicit descriptions of sexual behaviour.
Cassette. Needs 16K of RAM. $22.50. x-367s
has
Yv
2.
©
ai
Cd
O
Expanding The
System
EXPANDING THE SYSTEM
In order to expand your basic computer system you
need peripherals. A peripheral (the ‘ph’ is pronounced ‘f’
as in photo) is simply an ‘attachment’.
If you are buying a food processor the manufacturers
offer you a choice of attachments which you can add to
your basic machine so that it can perform additional
functions. The situation is exactly the same when you are
buying a computer — but instead of calling the extra
gadgets by the simple term ‘attachments’, computer jar--
gon uses the fancy word ‘peripherals’.
Taking the same analogy into the world of motor cars
... they are sold as the basic model or come with ‘extras’,
that is, attachments or peripherals. (Somehow I don’t
think that word will ever catch on down the Parramatta
Road.)
Therefore, any part of your computer set up which is
outside the all-in-one keyboard/memory/ processing
unit is a peripheral. Strictly speaking even a built-in
cassette player is a peripheral since it is not part of the
computer itself. The video monitor or normal TV screen
also falls into peripheral category. But let’s take a look at
some more interesting (if less basic) peripherals.
ipherals including an expansion unit,
two disk drives and a dot matrix printer ... all discussed and explained in
this chapter.
96
EXPANSION UNIT
This is a rectangular box-shaped device that is plugged
in to the rear of the keyboard and sits neatly behind it ona
desk or table. The unit has various sockets through which
other peripherals can be connected to the computer. The
System 80 expansion unit has the widely accepted indus-
try standard S-100 connection system, allowing you to
expand in almost any way you wish using compatible
products available from hundreds of manufacturers
around the world.
Lifting the lid off an expansion unit. Inside are all the components which
connect to various peripherals to expand the capabilities of your computer.
A SECOND CASSETTE
A second cassette player, in addition to the one built
into the computer, can be interfaced (connected) to the
main unit via the expansion unit.
DISK DRIVES
The only method of running and storing programs that
has been discussed in detail so far is the use of magnetic
97
tapes activated in a cassette player. Now it is time to
introduce the magnetic floppy disk — a small, flexible
disk which looks very much like a 45 rpm record inside a
cardboard sleeve. A floppy disk is revolved in a unit
called a disk drive which, to continue the music analogy,
is the approximate equivalent of a turntable.
The disk drive itself is a neat rectangular unit with a
vertical or horizontal slot (rather like a letter box) into
which the disk is inserted. On insertion the disk engages
and is revolved in the disk drive at about 300 rpm. As with
tapes, information 1s magnetically written on, stored on
or read from the disk.
A disk drive with floppy disks.
A disk drive works a little like a record player. The
read-write head moves across the disk tracks and picks up
or stores information. There is, however, a basic differ-
ence between a disk drive and a record player. The tracks
on a disk are concentric circles, each one separate from
the others. They don’t spiral towards the centre like the
grooves on a record. Each track is divided into 10 sectors
98
so that the computer can find the data required by locat-
ing the track and sector numbers of its storage place.
(Another difference between a computer disk anda regu-
lar record is that the floppy disk stays in its.sleeve &
rotates inside it — so don't try to get it out!)
How a disk drive works.
A disk drive is faster and more efficient to use than a
cassette player. It is also more expensive — understanda-
bly. The computer’s read-write head (an electromagnetic
head which reads or writes on disk or tape) finds the
desired segment on a disk far more quickly than ona tape
which has to be mechanically rewound before the desired
section can be located. A typical program taking a good
few minutes to load via tape will load in a matter of
seconds via disk.
Disk drives are recommended for serious business use
or by the keen enthusiast.
READING/.WRITING
When a disk drive or cassette recorder is transfer-
ring data to the central processing unit (CPU) it is
reading the data. When it is transferring it out of the
CPU, it 1s writing the data.
99
PRINTERS
These are the output devices that print out the results
of the computer’s work on paper. A printout of a file is
called a hard copy of that file. There are two main types of
printers.
Dot Matrix Printer |
This type of printer uses a series of dots to create the
characters you see on the page. It is fast but generally has
limited print quality.
A dot matrix printer. It prints on standard fan-fold sprocketted paper up to
240 mm wide at 125 characters per second. eg
Daisy Wheel Printer
This uses a variety of interchangeable daisy wheels
¢which work like the golf balls in an electric typewriter) to
type the characters on the page. A daisy wheel printer is
often slower than the dot matrix printer-but produces a
much more attractive result and is recommended for
word processing work. .
100
ty
A daisy wheel printer which produces sharp, clean copy suitable for word
processing.
LIGHT PEN
This is a very inexpensive peripheral which can add
another dimension to your computer entertainment or
serious use. The pen actually ‘sees’ darkness and light.
When it is touched to the screen the display can be altered
or erased. The pen can also be used to make sketches or
produce graphics on the screen.
101
MUSIC SYNTHESISER UNIT
This gadget opens the door to the uniquely different
and special world of computer sound. The unit itself is a
small box about 10 cm square that plugs into the back of
the keyboard unit enabling the computer operator to
generate music via a normal amplifier. In effect, you can
become a composer using both single notes and chords,
even if you can’t play an instrument!
A music synthesiser. The sockets, at left, are hooked up to a normal stereo
amplifier.
SPEECH SYNTHESISER UNIT
This remarkable device has really beneficial applica-
tions for handicapped people — the blind, the deaf and
Se: SSAA
‘ SSSA
102
the physically disabled. Letters or words can be typed on
the computer’s keyboard and they are then spoken aloud
via the synthesiser unit.
ACOUSTIC COUPLER MODEM
A unit which enables you to.connect your business
computer to your normal household telephone. Jn this
way you can communicate with any other computer any-
where in the world using the regular Telecom phone
system.
Within the time span of a few seconds, without leaving
your own home, you can...
103
‘@ Search the files of leading overseas newspapers
® Call up the very latest stock exchange, interest and
currency exchange rates from overseas
e Scan extracts of the latest research reports in any of
hundreds of fields including science, medicine and
engineering
® Communicate via the latest electronic mail
techniques
e Link up with overseas data banks
Over the last few years huge data bank services have
been established in the USA and other countries.
Hundreds of different data banks have been set up by
research bodies, universities, newspapers, hospitals,
stock exchanges and all kinds of public institutions.
All of this stored information is available (for a fee —
see over ) to anyone with a low cost personal or business
computer. MIDAS (Multimode International Data
Acquisition Service) offers this service to people any-
where in Australia — providing they have access to a
telephone. And the cost is the same whether you live in
Sydney, Perth or Alice Springs.
This small business computer has direct access to worldwide data banks via
the acoustic coupler modem attached to a normal telephone. Unfortunately,
this businessman is not using the coupler correctly. Can you spot the error?
See page 108 for clues.
104
In order to link a System 80 personal computer with
MIDAS you require a communications terminal pro-
gram. The business version of the same computer already
has this program built into it.
What Is MIDAS?
MIDAS is an international data communications link
operated by OTC (Overseas Telecommunications Com-
mission) which allows Australians to connect into the big
overseas data base networks and enjoy the facilities avail-
able to users in the USA and Canada, and shortly in the
UK and Europe as well. You connect to MIDAS by
dialling a special telephone number in Sydney. Calls to
this number are toll-free from anywhere in Australia, due
to a special agreement between OTC and Telecom Aus-
tralia. Asa MIDAS subscriber you pay only for the time
you spend hooked up on the data link itself, regardless of
whether you live in Sydney or on the other side of the
continent.
How Much Does It Cost?
Because OTC is using specially developed equipment
which lets many users ‘share’ the satellite link at the same
time, the cost is shared out too. You pay only around 20.
cents per minute, plus 60 cents for each 1000 characters of
information obtained. This is generally less than you’d
pay for an overseas telex, cable or telephone call.
Of course MIDAS itself only provides the link over-
seas — you still have to pay for the use of the various data
banks themselves. Like MIDAS, these generally charge
at quite modest rates. Typical rates vary from 60 cents to
$1.50 per minute.
Security
Could someone use your computer when you're not
there and run up a huge bill on your account? Not unless
you let them. When you register as a MIDAS user, you
are given details of the special MIDAS telephone number
together with your own special security password and
user code number. Without having these, no unautho-
105
rised person can use either your computer or their-own to
run up a bill on your account.
Is It Difficult To Use?
No — all you have to do 1s remember your password
and user number. Of course you also have to know how
to use the data bases you want to search, but you get
details on how to do this when you register with them.
How To Get Started
The first thing you need to do is contact the Customer
Systems Manager, Marketing Branch, OTC, at GPO
Box 7000, Sydney NSW 2001, or telephone (02) 230 5000,
and ask fora MIDAS application form and information.
If you let them know your occupation and the sort of
information you’d like to obtain by using MIDAS, OTC
may also be able to tell you which data bases are likely to
be of value to you, and how to register with them. If you
have a range of specialised interests, they may be able to
send you a directory for one of the data base networks.
Registering with MIDAS itself will cost you nothing.
This is also the case with many data bases. Although
some do charge a small registration fee, in general, you’re
charged only for your use of the services they provide.
You're not committed to any minimum time, either.
Once youre registered, using MIDAS 1s very easy. You
simply set your business computer for communications
terminal mode, dial up the MIDAS number, and join
your acoustic modem up to the telephone handset as
soon as you hear the tone. You then hit the ‘A’ key to let
MIDAS know what sort of a terminal you’re using. From
then, MIDAS itself guides you on the screen, and within
seconds you're talking to the overseas data base of your
choice.
If you are operating a personal computer, load the
communications terminal program, type in RUN toset it
going, and then tell it that you want ‘full duplex’ (F), and
that you don’t want added line feeds (N). Then dial up
MIDAS.
106
MIDAS User Information
For best results when using your coupler with tele-
phone handsets containing carbon granule microphones
please consider the following:—
= RESISTANCE
me DECREASES
—s
DIAPHRAGM. a
NORMAL =n
DIAPHRAGM
MOVES INWARDS
DIAPHRAGM
Most telephone handsets are fitted with carbon granu-
lar transmitters like those depicted above. When you
speak into the mouthpiece the sound waves strike a
diaphragm causing it to compress and release a chamber
filled with carbon granules. The change in density of the
granules causes a change in circuit resistance resulting in
a change from acoustic energy to electrical energy.
Carbon granules have packed
allowing little change in
resistance with changes in
107
When the. telephone handset is placed: in the acoustic:
coupler and used in the normal rest position of the
handset then after a short period of time the carbon.
granules begin to ‘pack’ and reliability decreases dramati-
cally. As the granules pack the change in resistance
decreases until ultimately this resistance does not accu-
rately convey the change in acoustic energy.
For best results the coupler should be used on its side:
thus orientating the telephone transmitter in the correct:
plane and thus preventing carbon granule packing.
These comments are valid — you can demonstrate to
yourself when next you are using the telephone by tilting
your head to one side so that the telephone microphone
has its axis vertical. Within a matter of moments your
Opposite number will be asking you to repeat what you.
have said. From this graphic demonstration you can
easily imagine .why the preceding comments are.
important. | :
REMEMBER if there is any doubt as to whether your
telephone has a carbon microphone or not, do not risk
108
difficulties — use the coupler correctly as illustrated, ON
ITS SIDE.
RIBBON CABLES
_ Ribbon cables, as illustrated here, are used to connect
the various units of the computer together — e.g. the
expansion unit to the computer, the printer to the expan-
sion unit, and so on.
109
Chapter
The Small Business
Computer
hj balls ;
Lan
Bi
THE SMALL BUSINESS COMPUTER
This book does not deal with computer systems that
sell for more than $10 000. (And most small computer set
ups are considerably cheaper than that!) If a small busi-
nessman* has reached the stage in the development of his
business where he feels that it would be more efficient,
cost and time effective to have a computer handle such
matters as the general ledger, payroll or inventory rather
than using conventional books and clerks, he has two
options.
The Options
1. Call in IBM, Hewlett Packard or some similar spe-
cialist firm. They will design a system to fit the particular
business’ needs — and they will usually do a superb job.
The snag? It will cost you an arm and a leg and the end
result, when measured against the cost of computer
installation, may not in fact save any money at all. (Hav-
ing a highly trained salesman come out and hold your
hand does not come cheap!)
2. Buy a personal or small business computer over the
counter. This will cost thousands and thousands of dol-
lars less than the specially designed system and will prob-
ably do just as good a job. The snag? You have to be
interested in learning how to make the computer and the
available software work for you. You'll be teaching your-
self as you adapt the system to fit in with your particular
business.
(Don’t misunderstand me, you don’t have to write your
own programs — at least not at first or unless you want to
— because there are all sorts of business procedure pro-
grams already written and available over the counter for
a few hundred dollars.) If yours 1s a small business, set up
on a fairly conventional basis, some of these programs
*Women’s Libbers, please note: of course | mean ‘businesswomen’ too, but it
would be very pedantic to repeat this continuously. So please take it as read.
11
Business is looking good!
will have equally as good an application to your business
as if they had been specially written for you.
20 Or Less Employees
Small business computers are becoming increasingly
popular in firms who have around 20 or less employees. A
company of this size would find it totally uneconomic to
buy a traditional computer — even if they could afford
the up front price.
However, take the case of a large firm of accountants.
Assuming that none of the partners were knowledgeable
about computing, the firm would definitely be better off
approaching one of the large computer companies and
spending around $20 000 to $30 000 for a system. They
would need to pay that amount to get the back-up knowl-
edge and service that would be required.
If you buy equipment from one of the large computer
companies, part of the price of the unit is a certain
112
amount of free programming time. However, there is no
such ‘luxury’ as free programming if you buy a small
business computer — that just doesn’t fit into the low cost
structure of an over-the-counter model.
Experience has shown that most small businessmen
who purchase a computer over the counter are practical
people, aware that the computer age is here, and inter-
ested in creating and adapting programs to dovetail in
with their own specialised business. This type of business-
man prefers to organise his own computer set-up and get
the machine going himself, rather than pay someone else
to do it.
Lack Of Confidence?
What about the person who can recognise the potential
of computers in business, but has absolutely no confi-
dence in his or her own ability to get to grips with a
computer?
In order to overcome this difficulty some over-the-
counter computer specialist companies (including mine)
have organised an inexpensive service where computer
purchasers can be helped to relax and become familiar
with their new business tool.
This is how it works in my company. For the very
reasonable price of $100 (at the time of going to press) an
independent computer consultant will give five hours of
assistance (spread over a short period) to anyone who has
purchased a computer. During that time the consultant
basically ‘hand-holds’ the new purchaser, showing him
how to make the most of the computer either by altering,
if necessary, ready written programs to suit his business,
or explaining how to input data specifically related to his
individual requirements. Usually it is a combination of
both situations.
Business Software
There is a large variety of programs available (see
Chapter 6) although, as explained, they sometimes have
to be adapted to some degree in order to be ideally
113
Bee Bo seas oe
If a small businessman lacks confidence in dealing with his computer an
independent consultant will give assistance for a very reasonable fee.
suitable. After a little bit of programming experience
such matters as wording, headings and layouts can easily
be changed so that the program is individualised.
Naturally, it helps the adaptation process if the pro-
grams have originated in Australia or have at least been
changed to cope with Australian conditions. For exam-
114
ple, American written programs don’t include a sales tax
component because, in the USA, that tax is paid by the
consumer in the store. The same principle applies to
dates. Americans write 3rd November, 1981 as 11/3/81,
which would be very confusing in an Australian business
environment.
A Typical Business Computer
$i “oe em i ti
TARTU TOUTE
The System 80 Mark 11 computer provides virtually all
the features of the basic personal computer together with
many extra ones designed to make it more suitable for
serious business use — for example, the numeric key pad
is an easy and efficient way to enter numbers.
Profit and growth are the aims of most businesses,
therefore it is logical to choose a computer that doesn’t
cost a fortune in the beginning but can be expanded as
your business expands and your profit grows. For exam-
ple, the basic computer illustrated above can be ex panded
into virtually three machines in one: an increased
memory capacity computer, a word processor and a data
communications terminal.
115
Appendix
116
APPENDIX
(Although I promised way back in Chapter One that I
wouldn't dazzle you with technology I don’t think this
book would be complete without a little more clarifica-
tion of the technical/ theoretical side of things. Skip it for
now, if you like — you're probably too busy teaching
yourself to type or pitting your wits against monsters!)
The information here 1s still very fundamental but it
will add to your understanding of computers and perhaps
give you a good grounding on which to build your knowl-
edge of programming and operating an expanded com-
puter system.
THE COMPUTER NUMBER SYSTEM
Although it is very adept with numbers a computer
does not ‘think’ about them in the same way as the human
brain. We use the decimal number system with digits
from 0 to 9. The computer uses the binary number sys-
tem, with. only two digits: 9 and 1.
This is not the place to explain the binary number
system, it is sufficient to say that various combinations of
these two numbers make up the ‘machine language’ in
which the computer responds to instructions.
Programming Languages
This machine language is very tedious and difficult for
human beings to use so computers have a permanently
inbuilt ‘interpreter’ program. When a programmer enters
instructions in a human-type language (such as BASIC
— the language used to program most personal compu-
ters) the interpreter program translates these instructions
to machine language.
. Because English (or Swahili, if it comes to that) is nota
very precise language, programmers enter their instruc-
tions in one of a variety of specifically developed pro-
gramming languages. Broadly speaking there are two
main types of programming languages:
117
High Level Languages
These are quite closely related to English. BASIC, for
example, is a high level language (see page 123). Other high
level languages are COBOL, FORTRAN, PASCAL and
FORTH. Languages like these are comparatively easy
for the programmer to use. Sometimes, however, they are
not close enough to the machine language to allow
detailed or complicated instructions to be entered.
Low Level Languages
These are much closer to machirie language. They are
more difficult for the programmer to use but they give
more flexibility and precision when writing complex pro-
grams. Assembly language is a low level language.
MORE ABOUT MEMORY
As you will remember that the computer has two
totally different types of memory: |
RAM (Random Access Memory) — a temporary
memory used to store data and programs. RAM can be
erased easily. (Very easily — a mere flick of the off switch
will do it!) See, Back Up.
ROM (Read Only Memory) — a permanent memory
built into the computer. This memory contains both the
interpreter program to translate input instructions into
machine language as well as the computer operating
system program.
The Operating System Program
This includes:
e Sets of instructions to pass data from the input
devices to the Central Processing Unit (CPU) and to pass
them out again to the output devices.
e Additional sets of instructions for finding informa-
tion on tapes of disk sectors.
@ Detailed orders to the CPU to respond in a particu-
lar way to each key on the keyboard.
It is by means of all the parts of the inbuilt ROM that
the CPU is able to accept instructions, perform arith-
118
metic and logic calculations, as well as organise and
control the other components of the computer system.
Disk Operating System (DOS)
This is a-special part of the operating system that,
unlike the rest of the system, resides in RAM memory.
This is a program of routine instructions to control the
storage and retrieval of information from disks. These
routines include allocating addresses to files (specifying
the track and sector in which they are stored), passing
information to and from the disk and listing the disk
directory for you. DOS typically uses about 7 kilobytes of
memory space.
Bits, Bytes & Kilobytes
In computer jargon the word bit (short for binary digit)
is the smallest individual memory position within the
computer. A group of 8 bits is known as a ‘byte’, which is
the usual amount of data that a personal computer can
process at one time. (There’s also the word nibble —
meaning four bits or half a byte — coined by some
computing nut with a logical sense of humour!)
A byte is roughly the equivalent of a character, i.e. a
letter, number, symbol or even the space left between
words.
There are 1024 bytes to one kilobyte (K) — a term
which has been mentioned several times earlier in the
book in connection with the computer’s memory. It has
been explained that the computer’s memory capacity
(both RAM and ROM) is usually expressed in terms of
K. (Don’t confuse this symbol K with the metric symbol k
(kilo) meaning 1000.)
Most personal computers have between 4K and 16K of
RAM and can be extended up to either 32K or 48K by the
addition of memory cards. A 48K memory, then, can
hold up to approximately 48 000 characters. This storage
space can be further increased by the use of external
storage on disk or tapes, thus leaving extra space in the
RAM. The computer can retrieve this data whenever it is
119
needed. This effectively increases the-size of the internal
RAM many times over.
Se
A plug-in memory card which adds an extra 16 or 32 K of RAM to anexisting
computer.
MORE ABOUT PROGRAMMING
As you'll remember from Chapter One, a program is
nothing more than a set of instructions for the computer.
Often a program is very detailed and contains thousands
of instructions, even though you can buy it on a single
small disk or cassette.
In developing a set of instructions the programmer
must work out every possible event that may occur dur-
ing the execution of the program and tell the computer
precisely what to do if that event happens. (Never forget:
the computer has absolutely no initiative.)
Preparing a program can involve a large number of
alternative actions for each step in the program, and a
large number of alternatives for each alternative, and so
on. It is very easy to leave something out or even to put an
instruction in the wrong place in the list. To avoid such
catastrophes the computer programmer uses a planning
aid called a flowchart. |
120
Below is a sample flowchart covering just the major
steps in going through a customer list and sending a
reminder letter to all customers who owe more than $100.
START
OPEN
FILES
IS :
TOTAL |
Vie
WRITE
NO LETTER
NO
YES CLOSE
FILES
Note that the chart goes through a Joop. That is, when
a customer has been dealt with (the computer has looked
at the file and decided whether or not to send the letter),
the computer returns to the next customer and repeats
the process.
121
Different types of functions are depicted in differently
shaped symbols. As you can see the diamond shape is
used for “decision making’ instructions which could yield
two or more possible results; and the rectangle for any
operation involving the use of an input or output device.
This is an easy flowchart which can be developed intoa
simple program. Before it is ready for use a program must
be rigorously tested to make sure that all possible events
are allowed for. This is a lot harder to do than it seems.
Mistakes in a program are called ‘bugs’ and the process
of correcting these mistakes is ‘debugging’. The more
complex the program, the more complex and difficult
this can become. .
Back Up
After you’ve gone to all the trouble to work out a
successful program don’t spoil it by being lazy. Make a
‘back up’ copy of it on another tape or disk so, if the
program is accidently erased, you always have it available.
Never forget how easy it is to lose a program ... if
someone trips over the power cord, if you turn off the
computer in error, if there’s a blackout ... there are
countless ways it could happen. A good backup system is
commonsense computing practice.
Systems
A set of programs 1s called a system. A debtors’ system,
for example, is a series of programs — one tells the
computer how to keep a name and address file for custo-
mers, another tells it how to print out statements for each
customer, another keeps track of the transactions carried
out each month and so on.
Designing a system involves several steps.
1. The initial ideas stage. You identify the problem
that you want the computer to be able to solve.
2. The assessment of the size and scope of the system
needed to solve the problem. In this stage you set the
objectives that you want the computer to meet.
3. The analysis phase where the programmer works
out the general specifications of the system.
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4, The design phase where the programmer plans the
system in detail.
5. The construction phase involves writing the pro-
gram, testing it and debugging it.
The finished system is copied onto disk or tapes and the
instruction manuals are written. The end result of all this
effort is a set of completed programs which are simple
and easy to use. When you buy a good program you will
never see the complexity of effort and design that has
gone into its production.
THE BASIC LANGUAGE
_. The most common language in personal computing is
BASIC. It is not difficult to learn since it approximates
English very closely. An easy way to explain the princi-
ples of the BASIC language is to run through the features
of the System 80 ‘Level II’ BASIC.
Firstly, this BASIC can be divided into nine sections.
1. ACTIVE COMMANDS
2. TEXT EDITING
. BASIC STATEMENTS
ARRAYS
STRINGS
. ARITHMETIC FUNCTIONS
. GRAPHICS
. SPECIAL FEATURES
. ERROR CODES
There are four different operating levels:
0 CONAN ADW
® Active Command Level
In this level, the computer responds to commands as
soon as they are entered (by pressing the NEW LINE key).
Whenever the >_ signs are on the display, the user is in
the active command level.
© The Program Execution Level
This level is entered by typing RUN, causing any
BASIC program in the memory to be executed.
123
© Text Editing Level
This level allows the user to modify, add or delete
characters and lines of the BASIC Program source resi-
dent in the memory. The most significant feature of this
level is that the user can change any portion of a line
without having to re-type the entire line.
@ Monitor Level
This level permits the user to load machine-language
programs into the memory. This may be a machine lan-
guage, executable programs or even data files.
1. Active Commands
1 AUTO
2 CLEAR
3 CLOAD
4 CLOAD?
5.CONT
6 CSAVE
7 DELETE
8 EDIT
9 LIST
10 NEW
1] RUN
12 SYSTEM
13 TROFF
14 TRON
15 LPRINT
16 LLIST
Automatic line numbering
Sets aside a specified amount of work
space for a program
Loads a program of specified filename
from a tape
Verifies that the loaded program is
correct
Continue execution after stopping
Saves BASIC program to tape
Deletes line or lines specified from
program
Activates EDIT mode to correct part of
a line
Lists the program lines specified
Clears the current program from
memory
Starts program execution
Activates Monitor mode
Turns off the trace diagnostic
Turns on the trace diagnostic
Prints a file to the printer
Lists the program to the printer
2. Text Editing
By typing in EDIT 100, for example, the computer will
124
prepare to edit line 100. You can:
I. Insert text
2. Delete from end of line
. Delete from cursor to end of line and insert text
. Add to end of line
. Quit and restart edit
. Change characters
3. Basic Statements
3
4
5. List line
6
7
1. PRINT
2. PRINT @
3. PRINT USING
4. INPUT
5. DATA
6. READ
7. RESTORE
8. PRINT #
9. INPUT #
4. Arrays
The computer is capable of accepting both numeric
and string arrays. An array is simply a list or table of data
which is set out in the memory of the computer for easy
access to programs. The dimension of an array is simply
the number of ways it is expanded from a single value.
Thus a table of data with eight columns and eight rows is
a two dimensional array containing sixty-four separate
variables. In the computer these are represented with
subscripts; e.g. A(1,1), A(1,2), A(1,3) ... A(8,8). These
125
. STOP
. GOTO
. GOSUB
. RETURN
. ON GOTO
. ON GOSUB
. FOR TO STEP
. NEXT
. RUN
. ON ERROR GOTO
. ERROR
arrays are set up in. the computer using the. DIM
statement.
5. Strings
The computer uses two kinds of strings:
1. Constants — these are always represented within
quotes inside the program; e.g. ‘yes’.
2. Variables — e.g. A$
As you can see, a string is simply a ‘string of charac-
ters’; they can, of course, be letters, numbers, or special
punctuation and mathematical characters. The computer
can add, divide, compare and create strings as you desire.
The functions ..it uses are:
1. ASC 6. MID$
2. CHR$. 7. STRS
3. LEFT$ 8. STRING$
4. RIGHT$ 9. VAL
5. LEN
6. Arithmetic Functions
The computer has sixteen built-in arithmetic functions:
1. ABS 9. INT
2: ATN 10. LOG
3. CDBL 11. RANDOM
4. CINT 12. RND
5. COS 13. SGN
6. SDNG 14. SIN
7. EXP 15. SQR
8. FIX 16. TAN
7. Graphics
The graphics of the computer are arranged as 48 lines
of 128 columns. The graphics commands available are
as follows:
1. SET ‘turns on’ a point
2. RESET ‘turns off’ a point
3. CLS ‘rubs out’ the complete screen
126
4: POINT lets the computer find out whether a:
particular point on the screen is ‘on’
or ‘off’.
8. Special Features
The following special features are implemented in the
computer:
1. INP This command will input the 8-bit byte
from the port specified.
2. OUT This command outputs a byte to the
port specified.
3. PEEK This command returns the decimal
value of the memory location specified.
4. POKE This command lets you insert a value
into the specified location in memory.
5. POS This command returns a number from
$ to 63 indicating the current cursor
position on the display line.
6. MEM This command returns the number of
unused and unprotected bytes in
memory.
7. USR This command calls a machine language
subroutine (or sub-program), and lets
the main program ‘pass’ a number to
the subroutine.
8. VARPTR_ This command lets a program find out
where a particular ‘variable’ number is
stored in the computer’s memory.
9. Error Codes
To assist in trapping errors in your programs, the
computer has twenty two error codes:
ERROR. ABBREV ERROR
CODE
| NF NEXT without FOR
2 SN Syntax error
3 RG RETURN without GOSUB
4 OD Out of date
5 FC Illegal function call
127
6 OV Overflow
7 OM Out of memory
8 UL Undefined line
9 BS Subscript out of range
10 DD Redimensioned array
11 /0 Division by 0
12 ID Illegal direct command
13 ™ Type mismatch
14 OS Out of string space
15 LS String too long
16 ST String formula too complex
17 CN Can't continue
18 NR No resume
19 RW RESUME without error
20 UE Unprintable error
21 MO Missing operand
22 FD Bad file data
Variables
A ‘variable’ is a number which can have different
values, so it is given a ‘name’. The computer accepts
variable names which can be longer than two characters.
However, only the first two characters will be recognised
as the variable name by the computer. Variable names
must start with a letter and the second character may bea
letter or a digit. Therefore variable names may be from
AA to ZZ and A@ to Z9. Please note however that when
using long variable names you must ensure that they do
not contain ‘reserved words’. These reserved words are
ones like ‘GOTO’, ‘PRINT’, ‘RUN’, etc.
Operators
The following ‘operators’ or mathematical operation
signs, are used by the computer:
+ Addition
_ Subtraction
* Multiplication
/ Division
128
ESC Exponentiation (raising to a power).
< Less than |
Greater than
<> Not equal
<= Less than or equal to
>= Greater than or equal to
= Equal to
In addition the computer recognises three logical
operators: |
AND, OR, NOT
and string operators for comparing the precedence’ of
strings.
129
Glossary
130
GLOSSARY
ACCESS: To retrieve information from the computer.
(The noun access has become the verb ‘to access’
in computer terminology.)
ADDRESS: Location of a specific storage ‘cell’ in
memory.
ALPHANUMERIC CHARACTERS: The characters
on the keyboard or screen which are either letters
or numbers.
ANALYST: A computer expert who studies the opera-
tions of a business company in order to design
a computer system that will enable the business to
operate at. maximum efficiency.
BACK-UP: A spare copy of programs, results etc. in case
the original tape or disk is lost, damaged or
erased in error from computer memory.
BASIC: A high level computer language. (Beginners All
Purpose Symbolic Instruction Code) BASIC is
the most commonly used language for personal
and small business computers. The language of
the instructional words is closely related to plain
English, and therefore easily learnt.
BINARY: A number system where each digit has one of
two number values — @ and 1. A counting system
using only the numbers | and 9, it is common to
all digital computers.
BIT: The smallest individual memory position within the
computer. Bit is derived from binary digit. (See
BYTE, KILOBYTE, NIBBLE.)
131
BOOTING or BOOTSTRAPPING: The act of loading
the first program into a computer after turning
It on.
BROWNOUT: A drop in the voltage supply going to the
computer through the mains.
BUFFER: A temporary storage area for memory.
BUG: An error in the program.
BYTE: This is the term for the usual amount of data that
a personal computer can process at one time.
Each byte is a group of 8 bits. (Larger computers
can process two or more bytes.) (See BIT, KILO-
BYTE.)
CPU: Central Processing Unit. The central ‘nerve cell’ of
the computer which performs the actual process-
ing of data arithmetically and logically. (See also
ROM and RAM.)
CARD: A printed circuit board which can be inserted or
plugged into the expansion unit of the computer
to increase memory capacity.
CASSETTE TAPE: A common material on which to
record and store (or retrieve) programs or data
for personal computers. It is identical in appear-
ance to the conventional cassette tape that
produces sound and uses the same magnetic tape
principle for recording and playing. It operates
on a normal cassette player. |
CHARACTER: A letter, digit or symbol (e.g. $) on the
computer keyboard that displays on the screen
when the key is pressed.
CHIP: A tiny piece of silicon with an integrated circuit
on it. Thousands of electronic components are
fitted onto a very thin sliver of silt:con about a
132
few millimetres square: Each memory chip
contains a fixed number of bits. (See BIT.)
COBOL: (Common Business Orientated Language) A
computer language often used for commercial
and business programs. |
COMMAND: An instruction given to the computer
when a program is running. The instruction to
print a file, for example, is a command.
CONFIGURATION: The arrangement and electrical
link-up of the hardware that comprises the
computer system. (See HARDWARE.)
CONTROLLER: A dedicated ‘slave’ computer that
takes over the detailed housekeeping for the disk
drives in response to broad commands from the
disk operating system (DOS) in the main com-
puter. (See DISK DRIVE and DOS.)
CRASH: The program fails ....dies ... bombs ... goes
away.
CURSOR: A small blinking signal (usually a short line
or rectangle) that lights up on the display screen
indicating where the next character pressed on
the keyboard will display.
DAISY CHAIN CABLE: A cable which links a series of
identical peripheral units. For example, a daisy
chain cable is used to link the disk drives to the
expansion unit. (See PERIPHERALS.)
DAISY WHEEL or PRINT WHEEL: This is a device
inside a printer which prints out characters and
operates in the same way as the golf ball ona
typewriter.
DATA: Information given to or received from the
computer.
133
DATA DISK: When two disk drives are being used to
run a program on the computer, one of the disks
is normally used for storing the program and is
called the System Disk. This disk generally has no
new material written on it. The other disk is
normally used to store the data that will be
entered (be it records of daily transactions or
additions to your inventory list). This is called the
Data Disk.
‘DATA PROCESSING: The processing of information
by a computer. The term generally refers to
business systems (e.g. payroll or inventory) as
distinct from scientific or other use.
DEDICATED COMPUTER: A small processor
designed to run on one program and carry outa
particular function. If you compare a computer
to a pianola, capable of using many different rolls
(or programs), the dedicated computer is more
like a music box, playing only one tune.
DEBUG: To get rid of an error (or errors) in the program.
DIGITAL: Electronic circuits which operate by a series
of On-Off switchings, rather than by varying a
continuous voltage or current.
DIP SWITCHES: A tiny bank of switches that plugs into
a circuit board like an integrated circuit or ‘chip’.
DIRECTORY: A list of the files stored on a given disk.
DISK: This is a circular disk, similar in appearance to a
45rpm record. Like cassette tape information is
recorded on its surface magnetically. It is used for
storing and reading data or programs. (See DISK
DRIVE, FLOPPY DISK, HARD DISK.)
DISK DRIVE: A mechanical unit of the total computer
set-up that records (writes), retrieves (reads) or
134
stores information on the disk. The disk drive has
a moving head that can record or read from any
part of the disk. Because the disk rotates very fast
(300rpm is normal) the head has almost immedi-
ate access to any point on the disk. This is a much
faster. way to retrieve information than having to
run through a cassette.
DISPLAY: A visual showing of the computer’s workings
or results. It is usually in the form of letters and
numbers lit up on a screen or printed out on
paper.
DOS or DISK OPERATING SYSTEM: A control pro-
gram that enables the computer operator to
transfer other programs and data to or from a
disk.
DUMP: To move data from one place to another e.g.
from memory to disk, from screen to printer,
from memory to printer.
EDIT: The most usual meaning is to correct the text
displayed on the screen by means of back spacing
over incorrect words, letters or numbers and
re-typing (i.e. entering) the correct data.
ENTER: To input or ‘feed’ information into the computer.
EXECUTE: To ‘run’ a program on the computer, i.e. to
tell the computer to perform a series of
instructions.
FIELD: One of the units of information in a complete
record system, e.g. name field, address field, etc.
FIRMWARE: A computer program stored permanently
in the computer, that cannot be erased or
changed. (See also ROM.)
135
FLOPPY DISK: A circular piece of flexible (floppy)
plastic, magnetised like recording tape, on which
programs for the computer are written, read or
stored. In appearance it is similar to a 45rpm
record. A floppy disk is permanently enclosed in
a card sleeve, even when in use. It is inserted into
the disk drive unit in order to perform its
functions. (See DISK DRIVE, HARD DISK.)
FLOWCHART: The graphical expression (usually
drawn and written with pencil and paper) of the
logical sequences in a computer program.
FORTRAN: A computer language. (Formula Trans-
lation.) This language is used in scientific and
mathematical programs.
GARBAGE: Meaningless data supplied by the computer
in response to meaningless data, or no data, fed
into it. (“Garbage in — garbage out.’)
GRAPHICS: The display of diagrams or drawings on
the video unit.
HALF BYTE: A group of four bits.
HARD COPY: Information from the computer in the
form of words or diagrams printed permanently
on paper, as distinct from being temporarily
displayed on the video unit.
HARD DISK: A disk similar to a floppy disk but made
of hard, non-flexible. material and capable of
storing far greater amounts of data. It is faster
but much more expensive than a floppy disk. (See
FLOPPY DISK.)
HARDWARE: The physical components which make
up the computer itself together with any units
136
that can be attached to the computer (see
PERIPHERALS), as distinct-from its programs
{see SOFTWARE).
HOME: The cursor’s starting point on the display screen.
INPUT: Information given to the computer. On personal
computers this is usually done by keying (typing)
it onto the keyboard or using magnetic cassette
tapes or disks.
INTERFACE: The connection of two or more electronic
units related to the computer set-up, e.g. connect-
ing a normal domestic TV set to the computer so
that the TV screen becomes the video display
unit on which information from the computer is
displayed. (When used as a verb, ‘to interface’
means ‘to connect’.)
INTEGRATED CIRCUIT: A_ complete electrical
circuit on an individual silicon chip.
KILOBYTE (K): The term or symbol used to express the
memory capacity of a computer. K = 1024 Bytes.
Thus, for example, 4K = 4096 bytes (4 « 1024).
The average personal computer has 16K of RAM
memory, but additional memory cards and the
use of peripherals can increase the computer’s
total RAM memory capacity. (See RAM and
PERIPHERALS.)
KEYBOARD: Similar in appearance to a typewriter
keyboard. This is standard on all personal
computers on which keys showing letters,
numbers or symbols are pressed to give (‘feed’ or
‘input’) information to the computer.
LANGUAGE: There are many different computer
languages which are broadly divided into two
137
levels — high and low. Obviously the software
(the program) must speak the same language as
the hardware (the computer). BASIC is the most
common (high-level) language for personal
computers.. |
LIGHT PEN: A pen-like instrument that is sensitive to
light and can be used to alter graphics, diagrams
or even words displayed on the video screen.
LOOP: A sequence of instructions which the computer
executes continuously and repeatedly until
ordered to stop.
MAGNETIC DISK: Used for the writing, storage or
retrieval of information. (See FLOPPY DISK
and HARD DISK.)
MAGNETIC TAPE: A thin plastic ribbon coated on one
side with iron oxide, so that it can be used for
magnetic recording and replay.
MAINFRAME: A very large computer.
MEGABYTE: One million bytes.
MENU: A list of choices offered by the computer and
displayed on the video monitor. The computer
operator chooses one of these.
MEMORY: A computer has two different types of
memory — fixed and permanent (see ROM —
READ ONLY MEMORY) and flexible and tem-
porary if desired (see RAM —RANDOM
ACCESS MEMORY.) The memory capacity of
a computer is expressed in bytes or kilobytes
(K = 1024 bytes). (See KILOBYTE.)
MODE: An aspect or kind of operation. EDIT mode,
when used in word processing for example,
allows you to change text in a file.
138
MODEM: A piece of equipment for sending binary codes
(computer machine language) over telephone
lines, thus allowing computers to send and receive
information on the telephone. The name stands
for MODulator/DEModulator.. The modulator
translates the binary code into whistles which can
be transmitted over the phone and the demodu-
lator translates the whistles back into binary code.
MICROCOMPUTER: A small computer such as a
personal computer used at home or in a small
business,
MICROPROCESSOR: The complete Central Pro-
cessing Unit (CPU) of the computer.
NIBBLE or NYBBLE: Half a byte or four bits.
OFF-LINE: Computer equipment which is not directly
a part of the computer, e.g. a printer which
produces printed hard copy from tape or disk:
ON-LINE: Computer equipment directly and perma-
nently connected to the computer and under the
control of the central processing unit.
OPTICAL SCANNING: Reading printed characters
and numbers by a light scanning device.
OPERATING SYSTEM: A series of programs fixed in
the computer which instruct it on how to carry
out its day to day operations. For example, the
procedure for transferring data from memory
to the video screen or printer 1s programmed into
the operating system.
OUTPUT: The visual display (usually on a sofeen or
printed paper) of either instructions given to the
computer, or answers supplied by the computer.
139
OVERWRITE: The act of recording over (and therefore
replacing) information on a disk or tape.
PASCAL: A computer language (named after the fam-
ous mathematician) that is growing in popularity.
PERIPHERALS: Units of hardware (see HARDWARE)
that attach to the main unit of the central pro-
cessor (see CPU) via an expansion unit, such as
disk drives, cassette players, printers and video
display units.
PORT: See INTERFACE.
PRINTER: A computer peripheral (attachment) that
prints information from the computer onto
paper. A serial printer prints one character at a
time; a line printer, one line at a time.
PROGRAM: A set of instructions for the computer to
obey. A program can be in the form of a cassette
tape, a disk, or instructions written on paper to be
typed into the computer’s keyboard.
PROGRAMMER: A person who writes a set of instruc-
tions for the computer.
RAM (RANDOM ACCESS MEMORY): Computer
memory which is used to store and retrieve both
-the data fed in by the computer operator and the
results calculated from the data. This memory
can be erased or altered at any time. (See also
ROM — READ ONLY MEMORY.) —
RANDOM ACCESS: The ability to access (either read
or write into) any byte of a memory system at
will without having to run through all the
preceding bytes. Semiconductor ‘drip’ memories
are random access devices. (See also SERIAL
ACCESS.) |
140
ROM (READ ONLY MEMORY): Permanent memory
information built-in to the computer during the
manufacturing process — for example, the
BASIC operating instructions and language.
ROM programs are sometimes known as FIRM-
WARE.
READ: Retrieving data in programs from the computers
memory or from disk or tape.
READ/WRITE HEAD: An electromagnetic head
which reads or writes on magnetic disk or tape to
retrieve or record information.
RF CONVERTOR: A unit that converts radio frequency
signals. For example, an RF convertor 1s used to
convert signals from the computer into signals
-like those from a TV station, so that a domestic
TV screen can be used to display information
from the computer.
RUN: To execute a program.
SOFTWARE: The program (in the form of a cassette
tape or disk) that is fed into the computer. Pro-
grams are written to perform specific tasks, e.g.
catalogue your stamp collection or prepare your
income tax return. Programs can be bought ready
made or they can be written by the user.
SERIAL ACCESS: Where the access to each byte of
memory storage is sequential and cannot be
selected at will. Cassette tapes are serial access
devices — the tape must be run through until the
desired place is reached (as in playing a music
cassette on a tape recorder). (See RANDOM
ACCESS.) |
‘SLAVE’ COMPUTER: A dedicated computer which is
141
part of a larger systém and: quite often controlled
by a general purpose computer.
SPIKE: A surge of extra voltage to the computer through
the electrical mains.
STRING: A set of characters in a particular, significant
order. A word, for example, is a string.
TAPE: See CASSETTE TAPE.
TERMINAL: The device which enables information to
be entered into the computer and then shown to
the operator. Personal computers have a typewriter-
like keyboard to enter information and a video
screen (or print out) for display.
WORD: The amount of data fed into or retrieved from
one memory location. In personal computers’
this is usually one byte.
WRITE: Recording data or programs in the computer’s
memory or on to a disk or tape.
WRITE PROTECT NOTCH or SENSING NOTCH:
A small notch on a disk which, when covered
with a ‘Write Protect Tab’, will prevent the com-
puter from recording or writing over data already
on the disk.
142
CLUB DIRECTORY
AUSTRALIAN CAPITAL
TERRITORY
Australian ZX80 Users’ Group
(AZUG); David Brudenall, 19
Godfrey St, Campbell, ACT 2061.
MICSIG; Registrar, PO Box 446,
Canberra 2601.
OMEGA (Ohio Scientific Micro-
computer Enthusiasts Group
Australia); Geoff Cohen, 72
Spofforth St, Holt, ACT 2165.
Sorcerer Computer Users of
Australia (ACT Branch); Mr G. T.
Dick, 31 Cresswell St, Campbell,
ACT 2601.
NEW SOUTH WALES
Apple Users Group (Sydney); PO
Box 505, Bankstown 2200. Phone
Colin Rutherford, (02) 520 0926.
Australasian ZX 80 Users News-
letter; 87 Murphys Avenue,
Keiraville, NSW 2500.
Commodore Users Group: John
Guidice, GPO Box 4721, Sydney
2001.
Compucolor Users Group: Andrew
MacIntosh, 91 Regent St, Chippen-
dale, Sydney 2008.
80-AT; The Australian 8080-Z80
Users Group; PO Box 165,
Lakemba 2195.
Macarthur Computer Users
Association; R. G. Friend, C/- 109
Campbellfield Ave, Campbelltown,
2560. Phone (046) 25 2752(A.H.) or
(046) 76 0541 extn 325 (Work).
MEGS; (Microcomputer Enthu-
siasts Group); John Whitlock, PO
Box 3, St. Leonards 2065.
Newcastle Microcomputer Club;
Gordon Johnson, Electron Micro-
scope Unit, University of New-
castle. Phone (049) 68 5045 (Work).
NSW 6800 User Group; 27 Geor-
gina Avenue, Keiraville, NSW
2500.
‘Richardson,
143
Sorcerers Users Group; PO -Box
E162, St. James 2001. Ian King,
15 Forest Avenue, Wahroonga
2076. Phone (02) 48 6072.
TI-99/4 Home Computer Users’
Group of Sydney; S. Andersen, PO
Box 101, Kings Cross, 2011. Phone
(02) 358 6662.
NORTHERN TERRITORY
The MicroComputer Association
of the Northern Territory; Andy
Smith, Darwin Community Col-
lege, Casuarina, NT.
Northern Territory 80 Computer
User Group; R. T. O’Brien, 433
McMillans Rd, Jingili, Darwin,
NT 5792.
QUEENSLAND
Brisbane Youth Computer Group;
A. Harrison, PO Box 396, Sunny-
bank 4109.
Commodore Computer Users
Group of Queensland; Mrs D. D.
Dillon, PO Box 127, Stones
Corner, 4120.
Iree Microcomputer Interest
Group; N. Wilson, PO Box 811,
Albion 4010.
Superboard Users Group, Ed
146 York Street,
Nundah, 4012.
SOUTH AUSTRALIA
Adelaide Micro User Group
(TRS-80 and System 80 Users);
R. G. Stevenson, 36 Sturt St,
Adelaide 5000.
South Australian Apple Users
Club; The Secretary, SAAUC, c/-
The Bookshelf, 169 Pirie Street,
Adelaide, 5000.
South Australian Microprocessor
Group Inc (SAMG); The Secretary,
PO Box 113, Plymton, 5038. Phone
(08) 278 7288.
TASMANIA
TAS-Micro; Peter Deckert, Unit
1/456 West Tamar Rd, Riverside,
Launceston, 7250.
Tasmanian OSI ‘Users Group;
David Tasker, 111 Bass Highway,
Westbury, 7303.
VICTORIA
Apple Users Society of Melbourne;
G. Halprin. Phone (03) 859 5835.
BUG 80; Burwood Users Group,
PO Box 46, Blackburn South 3130.
Compucolor Users Group; L.
Ferguson, 12 Morphett Avenue,
Ascot, Melbourme 3342. .
Geelong Computer Club; Peter
McKeon; PO Box 93, Geelong
3220.
KAOS (Ohio Scientific); David
Anear, 49 Millewa Crescent,
Dallas, 3047.
National ZX80 Users Club; 24 Peel
St, Collingwood, 3066.
Northern and Western Suburbs
Computer Users’ Group; contact
CP/M Data Systems, 284 Union
Rd, Moonee Ponds, 3039. Phone
John King (Secretary) (03) 338 9304.
144
SMUG; SCORD M100 users,
Robin Miller, 60 Winmalee Drive,
Glen Waverley 3150.
Sorcerer Computer Users (Aus-
tralia); Secretary, PO Box 144,
Doncaster 3108.
WESTERN AUSTRALIA
Sorcerer Computer Users of
Australia; The Secretary, 90 King
George St, South Perth 6151.
Phone (09) 367 6351.
CU WEST (WA Compucolor/
Intecolor User Group); John New-
man, 8 Hillcrest Drive, Darlington,
6070.
NEW ZEALAND
Wellington Microcomputer
Society Inc; Lindsay Williams,
2 Pope Street, Plimmerton, New
Zealand.
(Information, courtesy:
Your Computer)
Unlike other labour-saving machines which are built to do one
job only, the computer is designed to do many jobs. It is a teacher
one moment, an accountant the next and, when it’s time for games,
a fascinating and absorbing family entertainment centre. In less than
one minute, everybody, including children, can use a computer with
ready made programs.
WHAT IS A PERSONAL COMPUTER AND HOW
DOES IT WORK?
WHAT CAN A PERSONAL COMPUTER DO FOR YOU?
_ Entertainment ~ Domestic Monitor
_ Education _ Hobby Organization
_ Research Computing: The Hobby
_ Household Management ~ Small Business Management
GETTING STARTED IN COMPUTING AND
CHOOSING THE HARDWARE
A CLOSE-UP LOOK AT TWO TYPICAL PERSONAL
COMPUTERS
THE RANGE OF READY MADE PROGRAMS
EXPANDING THE SYSTEM
THE SMALL BUSINESS COMPUTER
2 ZEET SS2Z 0 NS!
et > Betting 2 know PERSONAL COMPUTERS ==
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